Revision as of 16:39, 3 July 2018

Text

Attachment 8 - NEDC-33576NP, Safety Analysis Report for Nine Mile Point Unit 2 Maximum Extended Load Line Limit Analysis Plus (Non-proprietary)
	ML13316B109
Person / Time
Site:	Nine Mile Point
Issue date:	11/01/2013
From:	; Constellation Energy Nuclear Group, EDF Group, Nine Mile Point
To:	; Office of Nuclear Reactor Regulation
Shared Package
ML13316B090	List: ML13316B107; ML13316B109; ML13316B110;
References
	DRF Section 0000-0138-0146, Rev. 6, NEDO-33576, Rev. 0
	Download: ML13316B109 (257)
	v • d • e

{{#Wiki_filter:ATTACHMENT 8NEDC-33576NP, SAFETY ANALYSIS REPORT FORNINE MILE POINT UNIT 2MAXIMUM EXTENDED LOAD LINE LIMIT ANALYSIS PLUS(NON-PROPRIETARY) Nine Mile Point Nuclear Station, LLCNovember 1, 2013 0HITACHIGE Hitachi Nuclear EnergyNEDO-33576 Revision 0DRF Section 0000-0138-0146 R6October 2013Non-Proprietary Information -Class I (Public)Safety Analysis ReportforNine Mile Point Unit 2Maximum Extended Load Line Limit Analysis PlusCopyright 2013 GE-Hitachi Nuclear Energy Americas LLCAll Rights Reserved NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION -CLASS I (PUBLIC)INFORMATION NOTICEThis is a non-proprietary version of the document NEDC-33576P, Revision 0, which has theproprietary information removed. Portions of the document that have been removed areindicated by an open and closed bracket as shown here [[IMPORTANT NOTICE REGARDING CONTENTS OF THIS REPORTPlease Read Carefully The design, engineering, and other information contained in this document is furnished for thepurposes of supporting the Constellation Energy Nuclear Group (CENG) license amendment request for a Maximum Extended Load Line Limit Analysis Plus at Nine Mile Point Unit 2 inproceedings before the U.S. Nuclear Regulatory Commission. The only undertakings of GEHwith respect to information in this document are contained in the contracts between GEH and itscustomers or participating utilities, and nothing contained in this document shall be construed aschanging that contract. The use of this information by anyone for any purpose other than that forwhich it is intended, is not authorized; and with respect to any unauthorized use, GEH makes norepresentation or warranty, and assumes no liability as to the completeness,

accuracy, orusefulness of the information contained in this document.

ii NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION -CLASS I (PUBLIC)TABLE OF CONTENTSPageExecutive Sum m ary ..................................................................................................................... ixA cronym s ...................................................................................................................................... xi1.0 Introduction .................................................................................................................... 1-11.1 Report Approach ........................................................................................................... 1-21.2 Operating Conditions and Constraints ........................................................................... 1-71.3 Sum m ary and Conclusions ............................................................................................ 1-92.0 Reactor C ore and Fuel Perform ance ........................................................................... 2-12.1 Fuel Design and Operation ............................................................................................ 2-12.2 Therm al Lim its A ssessm ent .......................................................................................... 2-32.3 Reactivity Characteristics .............................................................................................. 2-62.4 Stability .......................................................................................................................... 2-82.5 Reactivity Control ....................................................................................................... 2-142.6 Additional Limitations and Conditions Related to Reactor Core and FuelPerform ance ............................................................................................................ 2-153.0 Reactor C oolant and C onnected System s .................................................................... 3-13.1 N uclear System Pressure Relief and Overpressure Protection ...................................... 3-13.2 Reactor Vessel ............................................................................................................... 3-23.3 Reactor Internals ............................................................................................................ 3-33.4 Flow -Induced V ibration .............................................................................................. 3-103.5 Piping Evaluation ........................................................................................................ 3-133.6 Reactor Recirculation System ..................................................................................... 3-203.7 M ain Steam Line Flow Restrictors .............................................................................. 3-223.8 M ain Steam Isolation Valves ....................................................................................... 3-233.9 Reactor Core Isolation Cooling ................................................................................... 3-233.10 Residual Heat Rem oval System .................................................................................. 3-253.11 Reactor W ater Cleanup System ................................................................................... 3-264.0 Engineered Safety Features .......................................................................................... 4-14.1 Containm ent System Perform ance ................................................................................ 4-14.2 Em ergency Core Cooling System s ................................................................................ 4-64.3 Em ergency Core Cooling System Perform ance .......................................................... 4-104.4 M ain Control Room A tm osphere Control System ...................................................... 4-174.5 Standby G as Treatm ent System ................................................................................... 4-174.6 M ain Steam Isolation Valve Leakage Control System ................................................ 4-184.7 Post-LO CA Com bustible G as Control System ........................................................... 4-185.0 Instrum entation and C ontrol ........................................................................................ 5-15.1 N SSS M onitoring and Control ...................................................................................... 5-15.2 BO P M onitoring and Control ........................................................................................ 5-35.3 Technical Specification Instrum ent Setpoints ............................................................... 5-6iii NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION -CLASS I (PUBLIC)6.0 Electrical Pow er and A uxiliary System s ...................................................................... 6-16.1 A C Pow er ...................................................................................................................... 6-I6.2 D C Pow er ...................................................................................................................... 6-16.3 Fuel Pool ........................................................................................................................ 6-26.4 W ater System s ............................................................................................................... 6-36.5 Standby Liquid Control System .................................................................................... 6-46.6 H eating, Ventilation And A ir Conditioning .................................................................. 6-66.7 Fire Protection ............................................................................................................... 6-66.8 Other System s A ffected ................................................................................................. 6-77.0 Pow er C onversion System s ........................................................................................... 7-17.1 Turbine-G enerator ......................................................................................................... 7-17.2 Condenser and Steam Jet A ir Ejectors .......................................................................... 7-17.3 Turbine Steam Bypass ................................................................................................... 7-27.4 Feedw ater and Condensate System s .............................................................................. 7-28.0 R adw aste System s and Radiation Sources .................................................................. 8-18.1 Liquid and Solid W aste M anagem ent ........................................................................... 8-18.2 G aseous W aste M anagem ent ......................................................................................... 8-18.3 Radiation Sources in the Reactor Core .......................................................................... 8-38.4 Radiation Sources in Reactor Coolant ........................................................................... 8-38.5 Radiation Levels ............................................................................................................ 8-48.6 N orm al O peration O ff-Site D oses ................................................................................. 8-69.0 R eactor Safety Perform ance Evaluations .................................................................... 9-19.1 Anticipated Operational O ccurrences ............................................................................ 9-19.2 Design Basis Accidents and Events of Radiological Consequence .............................. 9-49.3 Special Events ............................................................................................................. 9-1010.0 O ther Evaluations ........................................................................................................ 10-110.1 H igh Energy Line Break .............................................................................................. 10-110.2 M oderate Energy Line Break ...................................................................................... 10-210.3 Environm ental Q ualification ....................................................................................... 10-310.4 Testing ......................................................................................................................... 10-510.5 Individual Plant Exam ination ...................................................................................... 10-610.6 Operator Training and Hum an Factors ...................................................................... 10-1110.7 Plant Life ................................................................................................................... 10-1210.8 N RC and Industry Com m unications ......................................................................... 10-1510.9 Em ergency and Abnorm al Operating Procedures ..................................................... 10-1511.0 Licensing Evaluations .................................................................................................. 11-111.1 Effect on Technical Specifications .............................................................................. 11-111.2 Environm ental A ssessm ent ......................................................................................... 11-111.3 Significant Hazards Consideration A ssessm ent .......................................................... 11-212.0 R eferences ..................................................................................................................... 12-1iv NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION -CLASS I (PUBLIC)Appendix A ............................................................................................................................ A -1Appendix B ............................................................................................................................. B-1A ppendix C ............................................................................................................................. C-1V NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION -CLASS I (PUBLIC)List of FiguresFigure Title PageFigure 1-1 Power/Flow Operating Map for MELLLA+ ........................................................ 1-14Figure 2-1 Power of Peak Bundle versus Cycle Exposure ..................................................... 2-22Figure 2-2 Coolant Flow for Peak Bundle versus Cycle Exposure ........................................ 2-23Figure 2-3 Exit Void Fraction for Peak Power Bundle versus Cycle Exposure ..................... 2-24Figure 2-4 Maximum Channel Exit Void Fraction versus Cycle Exposure ........................... 2-25Figure 2-5 Core Average Exit Void Fraction versus Cycle Exposure .................................... 2-26Figure 2-6 Peak LHGR versus Cycle Exposure ..................................................................... 2-27Figure 2-7 Dimensionless Bundle Power at BOC (200 MWd/ST) ........................................ 2-28Figure 2-8 Dimensionless Bundle Power at MOC (10,000 MWd/ST) .................................. 2-29Figure 2-9 Dimensionless Bundle Power at EOC (18,577 MWd/ST) .................................... 2-30Figure 2-10 Bundle Operating LHGR (kW/ft) at BOC (200 MWd/ST) .................................. 2-31Figure 2-11 Bundle Operating LHGR (kW/ft) at MOC (10,000 MWd/ST) ............................ 2-32Figure 2-12 Bundle Operating LHGR (kW/ft) at EOC (18,577 MWd/ST) ............................. 2-33Figure 2-13 Bundle Operating MCPR at BOC (200 MWd/ST) ............................................... 2-34Figure 2-14 Bundle Operating MCPR at MOC (10,000 MWd/ST) ......................................... 2-35Figure 2-15 Bundle Operating MCPR at EOC (18,577 MWd/ST) .......................................... 2-36Figure 2-16 Bundle Operating LHGR (kW/ft) at 15,000 MWd/ST (Peak MFLPD Point) ...... 2-37Figure 2-17 Bundle Operating MCPR at 1,500 MWd/ST (Peak MFLCPR Point) .................. 2-38Figure 2-18 Bundle Average Void History for Bundles with Low CPRs ................................ 2-39Figure 2-19 Required OPRM Arm ed Region ........................................................................... 2-40Figure 5-1 NMP2 EPU/M+ Power/Flow Map with 5% Voiding at the TIP ExitB ou n d ary ................................................................................................................ 5-9Figure 9-1 L R N B P at IC F ...................................................................................................... 9-26Figure 9-2 LRN BP at M ELLLA+ .......................................................................................... 9-27Figure 9-3 ODYN ATWS Analysis -PRFO at EOC Short-Term Results ............................ 9-28Figure 9-4 ODYN ATWS Analysis -MSIVC at EOC Long-Term Results .......................... 9-29Figure 9-5 ODYN ATWS Analysis -PRFO at EOC PCT .................................................... 9-30Figure 9-6 Single SLS Pump ODYN ATWS Analysis -PRFO at EOC Short-Term R e su lts .................................................................................................................. 9 -3 1Figure 9-7 Single SLS Pump ODYN ATWS Analysis -MSIVC at EOC Long-Term R e su lts .................................................................................................................. 9 -3 2Figure 9-8 Single SLS Pump ODYN ATWS Analysis -PRFO at EOC PCT ....................... 9-33Figure 9-9 ATWS Instability from MELLLA+ Operating Domain -Turbine Trip withF u ll B yp ass ........................................................................................................... 9-34vi NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION -CLASS I (PUBLIC)Figure 9-10 ATWS Instability from MELLLA+ Operating Domain -Turbine Trip withF u ll B yp ass ........................................................................................................... 9-35Figure 9-11 ATWS Instability from MELLLA+ Operating Domain -Recirculation P u m p T rip ............................................................................................................. 9-36Figure 9-12 ATWS Instability from MELLLA+ Operating Domain -Recirculation P u m p T rip ............................................................................................................. 9-37vii NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION -CLASS I (PUBLIC)List of TablesTable Title PageTable 1-1 Computer Codes Used in the M+SAR Evaluations .............................................. 1-10Table 1-3 Core Thermal Power to Core Flow Ratios ............................................................ 1-13Table 2-1 Peak N odal Exposures .......................................................................................... 2-17Table 2-2 Core Thermal Power to Core Flow Ratio at Steady-State and Off-Rated C o n d itio n s ............................................................................................................ 2 -18Table 2-3 TLO and SLO DSS-CD Licensing Basis Generic Applicability EnvelopeC hecklist C onfirm ation ........................................................................................ 2-19Table 2-4 [[................. 2-20Table 2-5 [[]].................................................................................................... 2 -2 1Table 3-1 K ey Results at 120% O LTP .................................................................................. 3-29Table 9-1 A OO Event Results Sum m ary .............................................................................. 9-17Table 9-2 Comparison of Slow Recirculation Flow Increase Results and MCPR FlowL im it ..................................................................................................................... 9 -18Table 9-3 Key Input Parameters for ATWS Analyses .......................................................... 9-19Table 9-4 Key Results for Licensing Basis ODYN ATWS Analysis ................................... 9-20Table 9-5 ODYN ATWS Analysis Limiting Event Results at MELLLA+ .......................... 9-21Table 9-6 Key Input Parameters for Single SLS Pump ATWS Analyses ............................. 9-22Table 9-7 Key Results for Single SLS Pump ODYN ATWS Analysis ................................ 9-23Table 9-8 Single SLS Pump ODYN ATWS Analysis Limiting Event Results .................... 9-24Table 9-9 Key Results for ATWS with Core Instability Analysis from MELLLA+O perating D om ain ................................................................................................ 9-25viii NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION -CLASS I (PUBLIC)EXECUTIVE SUMMARYThis report summarizes the results of all significant safety evaluations (SEs) performed thatjustify the expansion of the core flow (CF) operating domain for the Nine Mile Point Unit 2(NMP2) nuclear plant. The changes expand the operating domain in the region of operation withless than rated core flow (RCF), but do not increase the licensed power level or the maximumCF. The expanded operating domain is identified as Maximum Extended Load Line LimitAnalysis Plus (MELLLA+). The scope of evaluations required to support the expansion of the CF operating domain to theMELLLA+ boundary is contained in the Licensing Topical Report (LTR) NEDC-33006P-A, "Maximum Extended Load Line Limit Analysis Plus," referred to as the M+LTR (Reference 1).This report provides a systematic disposition of the M+LTR subjects applied to NMP2, including performance of plant-specific assessments and confirmation of the applicability of genericassessments to support a MELLLA+ CF operating domain expansion. It is not the intent of this report to address all the details of the analyses and evaluations reportedherein. Only previously Nuclear Regulatory Commission (NRC)-approved or industry-accepted methods were used for the analyses of accidents and transients. Therefore, because the safetyanalysis methods have been previously addressed, the details of the methods are not presented for review and approval in this report. Also, event and analysis descriptions that are alreadyprovided in other licensing reports or the updated safety analysis report (USAR) are not repeatedwithin this report.The MELLLA+ operating domain expansion is applied as an incremental expansion of theoperating boundary without changing the maximum licensed power or CF, or the current plantvessel dome pressure. This report supports operation of NMP2 at current licensed thermal power(CLTP) of 3,988 MWt with CF as low as 85% RCF following implementation of the extendedpower uprate (EPU) at NMP2. The terms CLTP and EPU are used interchangeably throughout this document, and refer to the same power level of 3,988 MWt. The MELLLA+ core operating domain expansion does not require major plant systems modifications. The core operating domain expansion involves changes to the operating power/core flow map, minor systemmodifications, procedure

changes, and changes to a small number of instrument setpoints.

Because there are no increases in the operating

pressure, power, steam flow rate, and feedwater (FW) flow rate, there are no significant effects on the plant systems outside of the nuclear steamsupply system (NSSS). There is a potential increase in the steam moisture content at certaintimes while operating in the MELLLA+ operating domain. The effects of the potential increasein moisture content on plant systems have been evaluated and determined to be acceptable.

TheMELLLA+ operating domain expansion does not cause additional requirements to be imposedon any of the safety, balance-of-plant (BOP), electrical, or auxiliary systems. No changes to thepower generation and electrical distribution systems are required as a result of the MELLLA+operating domain expansion. Evaluations of the reactor, engineered safety features (ESFs), power conversion, emergency power, support systems, environmental issues, and design basis accidents (DBAs) wereix NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION -CLASS I (PUBLIC)performed. The following conclusions summarize the results of the evaluations presented in thisreport.* All safety aspects of the plant that are affected by MELLLA+ operating domainexpansion were evaluated.

There is no change in the existing design basis and licensing basis acceptance criteria ofthe plant.* Evaluations were performed using NRC-approved or industry-accepted analytical methods." Where applicable, more recent industry codes and standards were used.* No major hardware modifications to safety-related equipment are required to supportMELLLA+ operating domain expansion.

" Systems and components affected by MELLLA+ were reviewed to ensure that there is nosignificant challenge to any safety system." Potentially affected commitments to the NRC were reviewed.

Planned changes not yet implemented have also been reviewed for the effects ofMELLLA+.This report summarizes the results of the SEs needed to justify a licensing amendment to allowthe MELLLA+ operating domain expansion to a minimum CF rate of 85% of RCF at 100%CLTP. These SEs demonstrate that the MELLLA+ operating domain expansion can beaccommodated:

" without a significant increase in the probability or consequences of an accidentpreviously evaluated;

without creating the possibility of a new or different kind of accident from any accidentpreviously evaluated; and" without exceeding any presently existing regulatory limits or acceptance criteriaapplicable to the plant that might cause a reduction in a margin of safety.Therefore, the requested MELLLA+ operating domain expansion does not involve a significant hazards consideration.

x NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION -CLASS I (PUBLIC)ACRONYMSTerm Definition 1 RPT One Recirculation Pump Trip2RPT Two Recirculation Pump TripABSP Automated Backup Stability Protection AC Alternating CurrentADS Automatic Depressurization SystemAL Analytical LimitALARA As Low As Reasonably Achievable ANS American Nuclear SocietyANSI American National Standards Institute AOO Anticipated Operational Occurrence AOP Abnormal Operating Procedure AOT Allowable Outage TimeAP Annulus Pressurization APRM Average Power Range MonitorARI Alternate Rod Insertion ARS Amplified Response SpectraART Adjusted Reference Temperature ARTS APRM / RBM / Technical Specifications ASME American Society of Mechanical Engineers AST Alternate Source Termatom % Percentage of AtomsATWS Anticipated Transient Without ScramAV Allowable ValueBOC Beginning of CycleBOP Balance-of-Plant BPV Boiler and Pressure VesselBSP Backup Stability Protection BSW Biological Shield WallBTU/Ibm BTU per Pounds MassBWR Boiling Water ReactorBWRVIP Boiling Water Reactor Vessel and Internals ProjectCDA Confirmation Density Algorithm CDF Core Damage Frequency xi NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION -CLASS I (PUBLIC)Term Definition cfmn Cubic Feet per MinuteCENG Constellation Energy Nuclear GroupCF Core FlowCFR Code of Federal Regulations CLTP Current Licensed Thermal PowerCO Condensation Oscillation COLR Core Operating Limits ReportCPR Critical Power RatioACPR Change in Critical Power RatioCRD Control Rod DriveCRDA Control Rod Drop AccidentCRGT Control Rod Guide TubeCS Core SprayCST Condensate Storage TankDBA Design Basis AccidentDC Direct CurrentDFFR Dynamic Forcing Functions ReportD/G Diesel Generator DIR Design Input RequestDOR Division of Responsibility DRF Design Record FileDSS-CD Detect and Suppress Solution-Confirmation DensityDSS-CD LTR DSS-CD Licensing Topical ReportDSS-CD TRACG LTR DSS-CD TRACG Licensing Topical ReportDTR Draft Task ReportDW DrywellECCS Emergency Core Cooling SystemsEDG Emergency Diesel Generator EFPY Effective Full Power YearEOC End of CycleEOOS Equipment Out-of-Service EOP Emergency Operating Procedure EPRI Electric Power Research Institute EPU Extended Power UprateEQ Environmental Qualification xii NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION -CLASS I (PUBLIC)Term Definition ESF Engineered Safety FeatureOF Degrees Fahrenheit FAC Flow Accelerated Corrosion FCV Flow Control ValveFHA Fuel Handling AccidentFIV Flow-Induced Vibration FTR Final Task ReportFW Feedwater FWCF Feedwater Controller Failure (Maximum Demand)FWHOOS Feedwater Heater(s) Out-of-Service GEH GE-Hitachi Nuclear Energy Americas LLCGESTAR General Electric Standard Application for Reactor FuelGNF Global Nuclear Fuel -Americas LLCgpm Gallons Per MinuteGWd/ST Gigawatt Days per Short TonHCTL Heat Capacity Temperature LimitHELB High Energy Line BreakHFCL High Flow Control LineHPCI High Pressure Coolant Injection HPCS High Pressure Core SprayHVAC Heating, Ventilation, and Air Conditioning IASCC Irradiated Assisted Stress Corrosion CrackingICF Increased Core FlowID Internal DiameterIGSCC Intergranular Stress Corrosion CrackingILBA Instrument Line Break AccidentIPE Individual Plant Examination IPEEE Individual Plant Examination of External EventsIRM Intermediate Range MonitorISI In-Service Inspection JPSL Jet Pump Sensing LineLAR License Amendment RequestLCO Limiting Condition for Operation LCS Leakage Control SystemLERF Large Early Release Frequency xiii NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION -CLASS I (PUBLIC)Term Definition LFWH Loss of Feedwater HeatingLHGR Linear Heat Generation RateLHGRFACf Linear Heat Generation Rate Flow FactorLOCA Loss-of-Coolant AccidentLOFW Loss of Feedwater LOOP Loss of Off-Site PowerLPCI Low Pressure Coolant Injection LPCS Low Pressure Core SprayLPRM Local Power Range MonitorLRNBP Generator Load Rejection Without BypassLTR Licensing Topical ReportMAPLHGR Maximum Average Planar Linear Heat Generation RateMCO Moisture Carryover MCPR Minimum Critical Power RatioMCPRr Flow-Dependent Minimum Critical Power RatioMCPR, Power-Dependent Minimum Critical Power RatioMCR Main Control RoomMELB Moderate Energy Line BreakMELC Moderate Energy Line CrackMELLLA Maximum Extended Load Line Limit AnalysisMELLLA+ Maximum Extended Load Line Limit Analysis PlusMFLPD Maximum Fraction of Limiting Power DensityMIP MCPR Importance Parameter M+LTR MELLLA+ Licensing Topical Report NEDC-33006P-A M+SAR MELLLA+ Safety Analysis Report (Plant Specific Safety Analysis Report)M+LTR SER MELLLA+ Safety Evaluation ReportMlbm/hr Millions Of Pounds Mass per HourMOC Middle of CycleMOP Mechanical Overpower MOV Motor-Operated ValveMPC Maximum Permissible Concentration MS Main SteamMSIV Main Steam Isolation ValveMSIVC Main Steam Isolation Valve ClosureMSIVF Main Steam Isolation Valve Closure with Scram on High Fluxxiv NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION -CLASS I (PUBLIC)Term Definition MSL Main Steam LineMSLBA Main Steam Line Break AccidentMWd/ST Megawatt Days per Short TonMWe Megawatt-Electric MWt Megawatt-Thermal NCL Natural Circulation LineNMP2 Nine Mile Point Unit 2NMPNS Nine Mile Point Nuclear Station, LLCNPSH Net Positive Suction HeadNRC Nuclear Regulatory Commission NSSS Nuclear Steam Supply SystemNTSP Nominal Trip SetpointOBE Operating Basis Earthquake OLMCPR Operating Limit Minimum Critical Power RatioOLTP Original Licensed Thermal PowerOOS Out-of-Service OPRM Oscillation Power Range MonitorPCT Peak Cladding Temperature PDI Performance Demonstration Initiative ppm Parts per MillionPRA Probabilistic Risk Assessment PRFO Pressure Regulator Failure -Openpsi Pounds per Square Inchpsia Pounds per Square Inch -Absolutepsid Pounds per Square Inch -Differential psig Pounds per Square Inch -GaugePWP Project Work PlanQA Quality Assurance QAP Quality Assurance ProgramRAI Request for Additional Information RBM Rod Block MonitorRCF Rated Core FlowRCIC Reactor Core Isolation CoolingRCPB Reactor Coolant Pressure BoundaryRE Responsible Engineerxv NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION -CLASS I (PUBLIC)Term Definition RG Regulatory GuideRHR Residual Heat RemovalRIPD Reactor Internal Pressure Difference RIS Regulatory Issue SummaryRLA Reload Licensing Analysisrpm Revolutions per MinuteRPS Reactor Protection SystemRPT Recirculation Pump TripRPTOOS Recirculation Pump Trip Out-of-Service RPV Reactor Pressure VesselRRS Reactor Recirculation SystemRSLB Recirculation Suction Line BreakRWCU Reactor Water CleanupRWE Rod Withdrawal ErrorRWM Rod Worth Minimizer SAD Amplitude Discriminator SetpointSAR Safety Analysis ReportSBO Station BlackoutSC Safety Communication SDC Shutdown CoolingSE Safety Evaluation SER Safety Evaluation ReportSGTS Standby Gas Treatment SystemSLMCPR Safety Limit Minimum Critical Power RatioSLO Single Loop Operation SLS Standby Liquid Control SystemSOP Special Operating Procedure SPC Suppression Pool CoolingSPDS Safety Parameter Display SystemSRLR Supplemental Reload Licensing ReportSRM Source Range MonitorSRO Strong Rod OutSRP Standard Review PlanSRV Safety Relief ValveSRVDL Safety Relief Valve Discharge Linexvi NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION -CLASS I (PUBLIC)Term Definition SRVOOS Safety Relief Valve -Out-of-Service SSE Safe Shutdown Earthquake STP Simulated Thermal PowerTAF Top of Active FuelTBVOOS Turbine Bypass Out-of-Service TFW Feedwater Temperature TIP Traversing Incore ProbeTLO Two Loop Operation T-M Thermal-Mechanical TOP Thermal Overpower TR Topical ReportTS Technical Specifications TSD Task Scoping DocumentTSTF Technical Specification Task ForceTSV Turbine Stop ValveTTNBP Turbine Trip Without BypassTTWBP Turbine Trip With BypassUHS Ultimate Heat SinkUSAR Updated Safety Analysis ReportUSE Upper Shelf EnergyV&V Verification and Validation VPF Vane Passing Frequency wt.% Percent by Weightxvii NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION -CLASS I (PUBLIC)

1.0 INTRODUCTION

This report summarizes the results of all significant SEs performed that justify the expansion ofthe operating boundary to NMP2 operation at a CLTP of 3,988 MWt and with CF as low as 85%of RCF. The terms CLTP and EPU are used interchangeably throughout this document, andrefer to the same power level of 3,988 MWt. The changes expand the operating domain in theregion of operation with less than RCF, but do not increase the licensed power level or themaximum CF. The expanded operating domain is identified as MELLLA+.The scope of evaluations required to support the expansion of the CF operating domain to theMELLLA+ boundary is contained in the LTR NEDC-33006P-A, "Maximum Extended LoadLine Limit Analysis Plus," referred to as the M+LTR (Reference 1). This report provides asystematic disposition of the M+LTR subjects applied to NMP2, including performance of plant-specific assessments and confirmation of the applicability of generic assessments to support aMELLLA+ CF operating domain expansion. The MELLLA+ core operating domain expansion does not require major plant hardwaremodifications. In accordance with Limitation and Condition 12.2 of the NRC Safety Evaluation Report (SER) for MELLLA+ (Reference 1), referred to as the M+LTR SER, NMP2 willimplement the Detect and Suppress Solution-Confirmation Density (DSS-CD)

solution, withlimitations and conditions as identified in the DSS-CD LTR SER (Reference 2), consistent withthe M+LTR. DSS-CD requires a revision to the existing stability solution software.

Theoperating domain expansion involves changes to the operating power/core flow map and changesto a small number of instrument setpoints. Because there are no increases in the operating

pressure, power, steam flow rate, and FW flow rate, there are no significant effects on the planthardware outside of the NSSS. There is a potential increase in the steam moisture content atcertain times while operating in the MELLLA+ operating domain. The effects of the potential increase in moisture content on plant hardware have been evaluated and determined to beacceptable.

The MELLLA+ operating domain expansion does not cause additional requirements to be imposed on any of the safety, BOP, electrical, or auxiliary systems. No changes to thepower generation and electrical distribution systems are required due to the introduction ofMELLLA+.This report also addresses applicable limitations and conditions as described in the M+LTR SERand the NRC SER for the GE-Hitachi Nuclear Energy Americas LLC (GEH) LTRNEDC-33173P-A, "Applicability of GE Methods to Expanded Operating Domains," referred toas the Methods LTR SER (Reference 3).The disposition of each limitation and condition is discussed along with the relevant section ofthis report. A complete listing of the required M+LTR SER, Methods LTR SER, and DSS-CDLTR SER limitations and conditions and the sections of this report which address them ispresented in Appendices A, B, and C, respectively. 1-1 NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION -CLASS I (PUBLIC)1.1 REPORT APPROACHThe evaluations provided in this report demonstrate that the MELLLA+ operating domainexpansion can be accomplished within the applicable safety design criteria. Many of the SEs andequipment assessments previously performed for the NMP2 EPU are unaffected because theMELLLA+ operating domain expansion effects are limited to the NSSS system.This NMP2 MELLLA+ safety analysis report (M+SAR) follows the same structure and contentas the M+LTR (Reference 1). Two dispositions of the evaluation topics are used to characterize the MELLLA+ evaluation scope. Topics are dispositioned as either "Generic" or"Plant-Specific" as described in Sections

1. 1.1 and 1.1.2, respectively.

1.1.1 Generic Assessments Generic assessments are those SEs that can be dispositioned by:* Providing or referencing a bounding analysis for the limiting conditions; " Demonstrating that there is a negligible effect due to MELLLA+;" Identifying the portions of the plant that are unaffected by the MELLLA+ power/flow map operating domain expansion; or* Demonstrating that the sensitivity to MELLLA+ is small enough that the required plantcycle-specific reload analysis process is sufficient and appropriate for establishing theMELLLA+ licensing basis in accordance with M+LTR SER Limitation andCondition 12.3.c and as defined in General Electric Standard Application for ReactorFuel (GESTAR) (Reference 4).As per M+LTR SER Limitation and Condition 12.4, the plant-specific MELLLA+application shall provide the plant-specific thermal limits assessment and transient analysis results. Considering the timing requirements to support the reload, the fuel andcycle-dependent analyses including the plant-specific thermal limits assessment may besubmitted by supplementing the initial M+SAR. Additionally, the Supplemental ReloadLicensing Report (SRLR) for the initial MELLLA+ implementation cycle shall besubmitted for NRC staff confirmation. Some of the SEs affected by MELLLA+ are fuel operating cycle (reload) dependent. Reload dependent evaluations require that the reload fuel design, core loading pattern,and operational plan be established so that analyses can be performed to establish coreoperating limits. The reload analysis demonstrates that the core design for MELLLA+meets the applicable NRC evaluation criteria and limits documented in Reference 4.1-2 NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION -CLASS I (PUBLIC)]] No plant can enter the MELLLA+ domain unless the appropriate reload core analysis is performed and all criteria and limits documented in Reference 4are satisfied. Otherwise, the plant would be in an unanalyzed condition. Based oncurrent requirements, the reload analysis results are documented in the SRLR, and theapplicable core operating limits are documented in the plant-specific Core Operating Limits Report (COLR).NMP2 will supplement this M+SAR with the fuel and cycle dependent analysis including the plant-specific thermal limits assessment. Additionally, NMP2 will submit the SRLRfor the initial MELLLA+ implementation cycle for NRC staff confirmation. As required by M+LTR SER Limitation and Condition 12.5.a, Nine Mile Point NuclearStation, LLC (NMPNS) will modify NMP2 Technical Specification (TS) 3.4.1 to includea requirement that prohibits intentional single loop operation (SLO) while in theMELLLA+ operating domain, as defined in the COLR. This information is presented inthe NMPNS MELLLA+ license amendment request (LAR) for NMP2.As required by M+LTR SER Limitation and Condition 12.3.b, the applicability of thegeneric assessments to NMP2 is identified and confirmed in the applicable sections. Inthe event that the generic assessment presented in the M+LTR is not applicable to NMP2,a plant-specific evaluation per Section 1. 1.2 is completed to demonstrate the acceptability of the MELLLA+ operating domain expansion. 1.1.2 Plant-Specific Evaluation A NMP2-specific evaluation is provided for SEs not categorized as Generic. Where applicable, the assessment methodology in References 1, 4, 5, 6, or 7 is referenced. As required by M+LTRSER Limitation and Condition 12.3.a, the plant-specific evaluations performed and reported inthis document use plant-specific values to model the actual plant systems, transient

response, andcurrent operating conditions.

1.1.3 Computer Codes and MethodsNRC-approved or industry-accepted computer codes and calculational techniques are used in theevaluations for the MELLLA+ operating domain. The primary computer codes used for NMP2evaluations are listed in Table 1-1. The application of these codes complies with the limitations, restrictions, and conditions specified in the approving NRC SER. Exceptions to the use of thecode or special conditions of the applicable SER are included as notes to Table 1-1.The Methods LTR NEDC-33173P-A (Reference

3) documents all analyses supporting theconclusions in this section that the application ranges of GEH codes and methods are adequate inthe MELLLA+ operating domain. In accordance with the M+LTR SER Limitation andCondition

12. 1, the range of mass fluxes and power/flow ratios in the GEXL database covers theintended MELLLA+ operating domain. The database includes low flow, high qualities, and voidfractions.

There are no restrictions on the application of the GEXL-PLUS correlation in theMELLLA+ operating domain.1-3 NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION -CLASS I (PUBLIC)As required by M+LTR SER Limitation and Condition 12.23.2, the NMP2-specific ODYN andTRACG calculations are provided to the NRC as required. As discussed in Section 1.0, the specific limitations and conditions associated with the M+LTR,Methods LTR, DSS-CD LTR, and DSS-CD TRACG LTR are discussed along with the relevantsection of this report. A complete listing of the required M+LTR SER, Methods LTR SER, andDSS-CD LTR SER limitations and conditions and the sections of this report which address themis presented in Appendices A, B, and C, respectively. 1.1.4 Scope of Evaluations Sections 2.0 through 11.0 provide evaluations of the MELLLA+ operating domain expansion onthe respective topics. The scope of the evaluations is summarized in the following sections. Section 2.0, Reactor Core and Fuel Performance: Core and fuel performance parameters areconfirmed for each fuel cycle, and will be evaluated and documented in the SRLR and COLR foreach fuel cycle that implements the MELLLA+ operating domain.Section 3.0, Reactor Coolant and Connected Systems: Evaluations of the NSSS components and systems are performed in the MELLLA+ operating domain. Because the reactor operating pressure and the CF are not increased by MELLLA+, the effects on the Reactor Coolant andconnected systems are minor. These evaluations confirm the acceptability of the MELLLA+changes to process variables in the NSSS.Section 4.0, Engineered Safety Features: The effects of MELLLA+ operating domainexpansion on the containment, emergency core cooling systems (ECCS), standby gas treatment system (SGTS), and other ESFs are evaluated. The operating pressure for ESF equipment is notincreased because operating pressure and safety relief valve (SRV) setpoints are unchanged as aresult of MELLLA+.Section 5.0, Instrumentation and Control: The instrumentation and control systems andanalytical limits (ALs) for setpoints are evaluated to establish the effects of MELLLA+ operating domain expansion on process parameters. The scope of MELLLA+ effects on the controls andsetpoints is limited because the MELLLA+ parameter variations are limited to the core.Section 6.0, Electrical Power and Auxiliary Systems: Because the power level is not changedby MELLLA+, the electrical power and distribution systems are not affected. The auxillary systems have been previously evaluated to ensure they are capable of supporting safe plantoperation at CLTP, which is unchanged by MELLLA+ operating domain expansion. Section 7.0, Power Conversion Systems: Because the pressure, steam flow, and FW flow donot change as a result of MELLLA+ operating domain expansion, the power conversion systemsare not affected by MELLLA+.Section 8.0, Radwaste Systems and Radiation Sources: The liquid and gaseous wastemanagement systems are not affected by the MELLLA+ operating domain changes. However,slightly higher loading of the condensate demineralizers is possible if the moisture carryover (MCO) in the reactor steam increases. The radiological consequences are evaluated to show thatapplicable regulations are met.1-4 NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION -CLASS I (PUBLIC)Section 9.0, Reactor Safety Performance Evaluations: The USAR anticipated operational occurrences (AOOs), DBAs, and special events are reviewed as part of the MELLLA+evaluation. Section 10.0, Other Evaluations: High energy line break (HELB) and environmental qualification (EQ) evaluations for the MELLLA+ domain are confirmed to demonstrate theoperability of plant equipment at MELLLA+ conditions. The effects on the individual plantexamination (IPE) are evaluated to demonstrate there is no significant change to the NMP2vulnerability to severe accidents. Section 11.0, Licensing Evaluations: This section includes the effect on TS. TheEnvironmental Assessment and the No Significant Hazards Consideration are provided as a partof the accompanying LAR.1.1.5 Product Line Applicability The M+LTR describes processes, evaluations, and dispositions applicable to GE boiling waterreactor (BWR) product lines BWR/3, BWR/4, BWR/5, and BWRI6. As such, the M+LTRprocess is applicable to NMP2, a BWR/5.1.1.6 Report Generation and Review ProcessThis M+SAR represents several years of project planning activities, engineering

analysis, technical verification, and technical review. The final stages of the M+SAR preparation includeM+SAR integration, additional review, on-site review committee review, and submittal to NRC.The NMP2 MELLLA+ project relied on the generic M+LTR (Reference

1) submitted to andapproved by the NRC (Reference 1).The project began with the respective GEH and NMPNS Project Managers creating a ProjectWork Plan (PWP). This PWP, developed in accordance with GEH engineering procedures, wasused to define the plant-specific work scope, inputs and outputs required for project activities.

Adivision of responsibility (DOR) between NMPNS and GEH was used to further develop thework scope and assign responsible engineers (REs) from each organization. A task scopingdocument (TSD) applicable for each GEH task was created,

reviewed, and approved by NMPNSprior to any technical work being performed.

Each GEH task RE submitted a design inputrequest (DIR) to the NMPNS task RE interface to define the correct plant information for use inthe GEH task analysis and evaluation. Additional DIRs were submitted as the project continued. A plant-specific M+SAR "shell" was created that contains the appropriate depth of information expected in the final M+SAR.All pertinent information is captured in an individual task design record file (DRF) maintained by the GEH RE with oversight by the respective engineering manager. Each DRF contains thequality assurance records applicable to the task, which includes evidence of design verification. A draft task report (DTR) was created for every GEH task. The DTR includes a description ofthe analysis performed, inputs, methods applied, results obtained and includes input to theapplicable M+SAR section(s). The DTR with M+SAR input was verified, in accordance withthe GEH quality assurance program (QAP), by a GEH technical verifier and a GEH Regulatory 1-5 NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION -CLASS I (PUBLIC)Affairs verifier, with oversight by the responsible GEH technical manager and GEH ProjectManager. The DTR with M+SAR input was transmitted by the GEH Project Manager toNMPNS and reviewed by the NMPNS RE and other NMPNS engineers, as appropriate. Subsequent comments were resolved between the GEH and the NMPNS REs and a final taskreport (FTR) with M+SAR input was developed. The FTR with M+SAR input was againverified (whether or not there were changes to the document), in accordance with the GEH QAP,by a GEH technical verifier and a GEH Regulatory Affairs verifier, with oversight by theresponsible GEH technical manager and GEH Project Manager. The GEH Project Managertransmitted the FTR with M+SAR input to the NMPNS Project Manager.For the NMP2 MELLLA+ project, NMPNS personnel:

1. Conducted multidisciplinary technical reviews of GEH evaluation reports (DTRswith M+SAR input and FTRs with M+SAR input) to ensure:i. Appropriate use of design inputs;ii. Consistency with the M+LTR; andiii. Design basis and licensing basis requirements were addressed.

2. Provided technical review results, in the form of detailed

comments, to GEHperformers;

3. Participated in discussions with GEH REs to address and resolve comments; and4. Controlled the application of the NMPNS off-site services process to GEH.The Regulatory Affairs RE integrated the individual M+SAR sections creating a Draft M+SARthat was verified, in accordance with the GEH QAP, by another GEH Regulatory Affairsengineer, with oversight by the GEH Regulatory Affairs Services Licensing Manager and theGEH Project Manager.

The GEH Project Manager transmitted the verified Draft M+SAR toNMPNS where it received another complete review by NMPNS's technical personnel, projectstaff, and Licensing staff.NMPNS personnel generated questions and comments, which were responded to by GEH'stechnical and Regulatory Affairs personnel. The M+SAR was then presented to the NMPNS'son-site review committee. After resolution of any final comments, the Final M+SAR wassubmitted to the NRC.A technical assessment of GEH's work was performed during reviews conducted at GEH officesin Wilmington, NC during January 2011. The scope of these assessments included workperformed by GEH and Global Nuclear Fuel -Americas LLC (GNF) in support of the NMP2MELLLA+ project. Participating in those activities were representatives of NMP2mechanical/structural,

nuclear, and reactor engineering disciplines, and project engineering.

TheNMP2 team reviewed design inputs, analysis methodologies, and results in the GEH DRFs. Thereviews included discussion with GEH technical task performers to obtain a thoroughunderstanding of GEH analysis methods.1.1.7 Report Generation and Review ProcessAs noted in Section 1.1.6 above, a DOR between NMPNS and GEH was used to further developthe work scope and assign REs from each organization. Tasks assigned to NMPNS REs were1-6 NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION -CLASS I (PUBLIC)performed under the NMPNS 10 Code of Federal Regulations (CFR) 50, Appendix B QAP,where applicable. The NMPNS assigned tasks were performed internally by NMPNS engineers or contracted out to engineering consulting firms on the NMPNS approved supplier list. Whereapplicable, the contractors applied a 10 CFR 50 Appendix B QAP.NMPNS internal tasks were prepared,

reviewed, and approved in accordance with applicable procedures.

For contracted tasks, a TSD applicable for each task was created,

reviewed, and approved byNMPNS prior to any technical work being performed.

This work scope formed the basis for theMELLLA+ task. The design inputs were then collected,

reviewed, and forwarded to theengineering consultant, in accordance with applicable procedures.

FTRs, and other engineering

products, when issued, are processed through the NMPNSengineering change process as a final verification of acceptability and retained as a quality recordin the NMPNS nuclear records management system.1.2 OPERATING CONDITIONS AND CONSTRAINTS 1.2.1 Power/Flow MapThe NMP2 power/flow map including the MELLLA+ operating domain expansion is shown inFigure 1-1. [[All lines on the power/flow map in Figure 1-1, other than those associated with the MELLLA+operating domain expansion, are unchanged by MELLLA+.As required by M+LTR SER Limitation and Condition 12.5.c, NMP2 will include thepower/flow map in the COLR after the MELLLA+ operating domain expansion is approved.

The MELLLA+ domain extends from 55% RCF at 77.6% EPU to 85% RCF at 100% EPU.Normal core performance characteristics for plant power/flow maneuvers at near full power canbe accomplished above 55% CF. Due to stability considerations at high power and low CF, theMELLLA+ domain was not extended below 55% RCF. The reactor operating conditions following an unplanned event could stabilize at a power/flow point outside the allowed operating domain. If this occurs the operator must reduce power or increase flow in accordance with plantprocedures to place the plant back into the allowed operating domain.The steady-state core thermal power to CF ratio for operation in the MELLLA+ domain is listed inTable 1-3. Each point listed is in compliance with the Methods LTR SER Limitation andCondition 9.3 of 50 MWt/Mlbmihr with the exception of the point of low flow/ high power, point'M' (55% RCF / 77.6% EPU), on Figure 1-1. The point on the power/flow map is only marginally above the limit and is not used for extended periods of operation. Because the limitation is notintended to place operational restrictions on the plant (Reference 3.c), the NMP2 MELLLA+power/flow map shall remain as shown in Figure 1-1, without any additional restrictions. 1-7 NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION -CLASS I (PUBLIC)As NMP2 exceeds the power-to-flow ratio of 50 MWt/Mlbm/hr at 55% RCF, an assessment of thelimitation with respect to the conservatism of the power distribution uncertainties is performed. Theresults of this assessment are provided in Section 2.2.5.1.2.2 Reactor Heat BalanceThe reactor heat balance is affected. Operation in the MELLLA+ domain, with lower CF, results ina decrease in recirculation pump heat and core inlet enthalpy. 1.2.3 Core and Reactor Conditions As mentioned previously, the MELLLA+ operating domain expansion results in changes to thecore and reactor.Table 1-2 compares Maximum Extended Load Line Limit Analysis (MELLLA) and MELLLA+thermal-hydraulic operating conditions for NMP2. The differences shown in Table 1-2 aretypical of other BWR plants analyzed for MELLLA+ operating domain expansion, and the coreoperating conditions listed in Table 1-3 represent the maximum allowed power-to-flow ratiostatepoints within the boundaries of the MELLLA+ operating domain. [[]]The decay heat is principally a function of the reactor power level and the irradiation time. TheMELLLA+ operating domain expansion does not alter either of these two parameters, andtherefore, there is no first order effect on decay heat. Enrichment,

exposure, void fraction, powerhistory, cycle length, and refueling batch fraction have a second order effect on decay heat.1]1.2.4 Operational Enhancements The following table provides the performance improvement and/or equipment out-of-service (EOOS) features applicable to NMP2 and whether they are allowed in the MELLLA+ operating domain. The table also dispositions other operational enhancements that were discussed in theM+LTR (Reference 1).Operational Enhancements MELLLA+ NMP2 M+SARIncreased Core Flow (ICF) Allowed IncludedSingle Loop Operation Not Allowed Not IncludedSafety Relief Valve -Out-of-Service (SRVOOS)

(2 valves) Allowed IncludedAverage Power Range Monitor (APRM) / Rod Block Allowed IncludedMonitor (RBM) / Technical Specifications (ARTS)Recirculation Pump Trip Out-of- Service (RPTOOS) Allowed Included1-8 NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION -CLASS I (PUBLIC)Turbine Bypass Out-of-Service (TBVOOS) Allowed IncludedMain Steam Isolation Valve (MSIV) Out-of-Service (OOS) Allowed IncludedTwo Automatic Depressurization System (ADS) Valves Out- Allowed Includedof-Service 20'F FW Operational Temperature Band Allowed Included24 Month Cycle Allowed Included60-Year Plant Life Allowed IncludedThe evaluations performed in support of MELLLA+ operating domain expansion consider eachof the operational enhancements listed as "Allowed." Because the operational enhancements areconsidered as a part of the design inputs for evaluations performed in support of MELLLA+operating domain expansion, these operational enhancements are evaluated across the scope ofthis M+SAR and are therefore not dispositioned in a specific section.The existing NMP2 License Condition 7 restricts operation with FW heating to within20 degrees of the design FW temperature which satisfies M+LTR SER Limitation andCondition 12.5.b.SLO in the MELLLA+ domain is not proposed. The present licensing basis for SLO remainsapplicable per plant TS.As required by M+LTR SER Limitation and Condition 12.5.a, NMPNS will modify NMP2TS 3.4.1 to include a requirement that prohibits intentional SLO operation while in theMELLLA+ operating domain as defined in the COLR. This information is presented in theNMPNS MELLLA+ LAR for NMP2.1.3 SUMMARY AND CONCLUSIONS This M+SAR documents the results of analyses necessary to expand the operating domain of theNMP2 plant to include the MELLLA+ domain. This document conforms to the scope, contentand structure described in the M+LTR, which the NRC has determined "is acceptable forreferencing in licensing applications for GE-designated boiling water reactors to the extentspecified and under the limitations and conditions delineated in the TR [topical report] and in theenclosed final SE [safety evaluation]." 1-9 NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION -CLASS I (PUBLIC)Table 1-1 Computer Codes Used in the M+SAR Evaluations Task Computer Version or NRC CommentsCode* Revision ApprovedReactor Heat Balance ISCOR 09 Y(l) NEDE-2401 IP Rev. 0 SERReactor Core and Fuel TGBLA 06 Y(2) NEDE-30130P-A Performance PANACEA 11 Y(2) NEDE-30130P-A ISCOR 09 Y(l) NEDE-240I P Rev. 0 SERPRIME 03 Y(17) NEDC-33256P-A Revision I,NEDC-33257P-A Revision 1,NEDC-33258P-A Revision 1Thermal Hydraulic Stability ODYSY 05 Y NEDC-33213P-A TRACG 04 Y(14) NEDE-33147P-A Rev. 4ISCOR 09 Y(l) NEDE-2401 IP Rev. 0 SERPANACEA II Y(3) NEDE-30130P-A Reactor Internal Pressure LAMB 07 (4) NEDE-20566P-A, September 1986Differences TRACG 02 Y(5) NEDE-32176P, Rev. 0, February 1993NEDE-32177P, Rev. 1, June 1993NRC TAC No. M90270, Sept. 1994ISCOR 09 Y(l) NEDE-2401 1P Rev. 0 SERReactor Recirculation BILBO 04V (8) NEDE-23504, Feb. 1977System (RRS)Reactor Pressure Vessel TGBLA 06 Y(2) NEDE-30130P-A (RPV) Fluence DORTG 01 Y(l 1, 12) CCC-543Containment System M3CPT 05 Y NEDO-10320, April 1971 (Reference 8)Response and NUREG-0808 (Reference 9)NEDE-20566P-A, September 1986LAMB 08 (4) (Reference 10)Break Flow Mass/Energy TRACG 04 N(I 5) NEDE-32176P Rev. 4, January 2008Release Rates NEDE-32177P Rev. 3, August 2007NEDO-33083-A Rev. 1, September 2010Annulus Pressurization (AP) ISCOR 09 Y(l) NEDE-2401 IP Rev. 0 SERLoads GOTHIC 7.2b N(16)AP Loads -RPV and SAP4G 07 N(8) NEDO-10909, Rev. 7, December 1979Internals' Structural SPECA 05 N(8) NEDE-25181, August 1996Analysis PDA 02 N(8) NEDE-10813A, February 1976ECCS-Loss-of-Coolant LAMB 08 Y NEDE-20566P-A Accident (LOCA) PRIME 01 Y(17) NEDC-33256P-A, Rev. 101 Y NEDC-33257P-A, Rev. 101 Y NEDC-33258P-A, Rev. ISAFER 04 Y (9) (10)ISCOR 09 Y(l) NEDE-2401 IP Rev. 0 SERTASC 03 Y NEDC-32084P-A 1-10 NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION -CLASS I (PUBLIC)Task Computer Version or NRC CommentsCode* Revision ApprovedTransient Analysis PANACEA 11 Y NEDE-30130P-A (6)ODYN 09 Y NEDE-24154P-A (Reference Ii)NEDC-24154P-A, Vol. 4, Sup I(Reference 11)ISCOR 09 Y(1) NEDE-2401 IP Rev. 0 SERTASC 03 Y NEDC-32084P-A Rev. 2Anticipated Transient ODYN 09 Y NEDC-24154P-A, Vol. 4, Sup. IWithout Scram (ATWS) STEMP 04 (7)PANACEA 11 Y(6)TASC 03A Y NEDC-32084P-A Rev. 2ISCOR 09 Y(l) NEDE-2401 IP Rev. 0 SERTRACG 04 N(I 3) 1__The application of these codes to the MELLLA+ analyses complies with the limitations, restrictions, andconditions specified in the approving NRC SER where applicable for each code. The application of the codesalso complies with the SERs for the MELLLA+ programs. Notes for Table 1-1:(1) The ISCOR code is not approved by name. However, in the SER supporting approval of NEDE-2401 1PRevision 0 by the May 12, 1978 letter from D. G. Eisenhut (NRC) to R. Gridley (GE), the NRC finds themodels and methods acceptable for steady-state thermal-hydraulic

analysis, and mentions the use of a digitalcomputer code. The referenced digital computer code is ISCOR. The use of ISCOR to provide corethermal-hydraulic information in reactor internal pressure differences (RIPDs),

transient, ATWS, stability, and LOCA applications is consistent with the approved models and methods.(2) The use of TGBLA Version 06 and PANACEA Version 11 was initiated following approval of Amendment 26 of GESTAR II by letter from S. A. Richards (NRC) to G. A. Watford (GE)

Subject:

"Amendment 26 toGE Licensing Topical Report NEDE-2401 1P-A, GESTAR II Implementing Improved GE Steady-State Methods (TAC NO. MA648 1)," November 10, 1999.(3) The use of PANACEA Version 11 was initiated following approval of Amendment 26 of GESTAR II byletter from S. A. Richards (NRC) to G. A. Watford (GE)

Subject:

"Amendment 26 to GE Licensing TopicalReport NEDE-24011P-A, GESTAR II Implementing Improved GE Steady-State Methods," (TACNO. MA6481), November 10, 1999.(4) The LAMB code is approved for use in ECCS-LOCA applications (NEDE-20566P-A), but no approving SERexists for the use of LAMB for the evaluation of RIPDs or containment system response. The use of LAMBfor these applications is consistent with the model description of NEDE-20566P-A. (5) NRC has reviewed and accepted the TRACG application for the flow-induced loads on the core shroud asstated in NRC SER TAC No. M90270.(6) The physics code PANACEA (PANAC) provides inputs to the transient code ODYN. The use of PANACEAVersion 11 in this application was initiated following approval of Amendment 26 of GESTAR II by letterfrom S. A. Richards (NRC) to G. A. Watford (GE)

Subject:

"Amendment 26 to GE Licensing Topical Report1-11 NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION -CLASS I (PUBLIC)NEDE-2401 I P-A, GESTAR II Implementing Improved GE Steady-State Methods," (TAC NO. MA648 1),November 10, 1999.(7) The STEMP code uses fundamental mass and energy conservation laws to calculate the suppression poolheatup. The use of STEMP was noted in NEDE-24222, "Assessment of BWR Mitigation of ATWS,Volume I & II (NUREG-0460 Alternate No. 3) December 1, 1979." The code has been used in ATWSapplications since that time. There is no formal NRC review and approval of STEMP or the ATWS TR.(8) Not a safety analysis code that requires NRC approval. The code application is reviewed and approved byGEH for "Level-2" application and is part of GEH's standard design process. The application of this codehas been used in other MELLLA+ and power uprate submittals. (9) "SAFER Model for Evaluation of Loss-of-Coolant Accidents for Jet Pump and Non-Jet Pump Plants,"NEDE-30996P-A, General Electric

Company, October 1987.(10) Letter, Richard E. Kingston (GEH) to NRC, "Transmittal of Revision 1 of NEDC-32950, Compilation ofImprovements to GENE's SAFER ECCS-LOCA Evaluation Model," MFN 07-406, July 31, 2007.(11) CCC-543, "TORT-DORT Two- and Three-Dimensional Discrete Ordinates Transport Version 2.8.14,"Radiation Shielding Information Center (RSIC), January 1994.(12) The use of DORTG was approved by the NRC through the letter from H. N. Berkow (NRC) to G. B.Stramback (GE), "Final Safety Evaluation Regarding Removal of Methodology Limitations forNEDC-32983P-A, General Electric Methodology for Reactor Pressure Vessel Fast Neutron Flux Evaluations (TAC No. MC3788),"

November 17, 2005.(13) The TRACG04 code is not approved by the NRC for long-term ATWS calculations including ATWS withdepressurization and ATWS with core instability.

However, TRACG04 is used as a best-estimate code, whileODYN remains as the licensing basis code for ATWS consistent with the NRC SE for NEDC-33006P.

Theuse of TRACG04 for the best-estimate TRACG ATWS analysis is also consistent with the NRC SE forNEDC-33006P. TRACG04 is approved by the NRC for application to ATWS overpressure transients inNEDE-32906P Supplement 3-A, "Migration to TRACGO4 / PANAC 1I from TRACG02 / PANAC1O forTRACG AOO and ATWS Overpressure Transients," April 2010.(14) The TRACG04 application for DSS-CD is documented in NEDE-33147P-A Revision 4 (Reference 12).(15) The TRACG break flow model and qualification basis is described in NEDE-32176P and NEDE-32177P. The application of TRACG04 for the calculation of break flow mass/energy release rates has been approvedfor ESBWR LOCA application in NEDO-33083-A. (16) GOTHIC quality assurance (QA) Version 7.2b has been applied in several NRC approved primarycontainment/subcompartment evaluation analyses including the NMP2 EPU peak pressure evaluations toaddress GEH Safety Communication (SC) 09-05 submitted on October 8, 2010 (Reference 13). Theassociated NRC SER for the NMP2 EPU LAR was issued on December 22, 2011 (Reference 14).(17) Application of PRIME models and data to downstream methods is approved by NEDO-33173 Supplement 4-A, "Implementation of PRIME Models and Data in Downstream Methods," Revision 1,November 2012 (Reference 3).1-12 NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION -CLASS I (PUBLIC)Table 1-2 Comparison of Thermal-Hydraulic Parameters MELLLA MELLLA+ MELLLA+Parameter 100% CLTP, 100% CLTP, 77.6% CLTP,99% Core Flow 85% Core Flow 55% Core FlowThermal Power (MWt) 3988 3988 3095Dome Pressure (psia) 1035 1035 1011Steam Flow Rate (Mlbm/hr) 17.636 17.633 13.115FW Flow Rate (Mlbm/hr) 17.604 17.601 13.083FW Temperature ('F) 440.5 440.5 411.4Core Flow (Mlbrn/hr) 107.4 92.2 59.7Core Inlet Enthalpy (BTU/Ibm) 528.7 525.2 511.4Core Pressure Drop (psi) 25.0 20.2 10.7Core Average Void Fraction 0.504 0.531 0.532Core Exit Void Fraction 0.723 0.755 0.766Table 1-3 Core Thermal Power to Core Flow RatiosPoint on the Core Thermal Core Flow Power-to-Flow Steady-State Operation Power/Flow Power RatioMap (MWt/%CLTP) (Mlbm/hr/%rated) (MWt/Mlbm/hr) Current Operating Domain E 3988 /100 108.5 /100 36.76100% Rated Core FlowCurrent Operating Domain D 3988 / 100 107.4/99 37.1399% Rated Core FlowMELLLA+Operating Domain N 3988 /100 92.2 / 85 43.2485% Rated Core FlowMELLLA+Operating Domain M 3095 / 77.6 59.7 / 55 51.8655% Rated Core Flow1-13 NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION -CLASS I (PUBLIC)Core Flow (Mlbm/hr) 0 10 20 30 40 50 60 7080 90 100 110 120 1301201101009080f"7060so3020100100% CLTP = 3988 MWt86.9% CLTP (Pre-EPU) 3467 MWt100% Core Flo1 = 108.5 Mlbrn/hr450040003500300025002000 Ei150010005000 10 20 30 40 50 60 70 80 90 100 110 120Core Flow (%)Figure 1-1 Power/Flow Operating Map for MELLLA+1-14 NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION -CLASS I (PUBLIC)2.0 REACTOR CORE AND FUEL PERFORMANCE This section addresses the evaluations that are applicable to MELLLA+.Because NMP2 currently uses only GE14 fuel, the following limitations and conditions from theMethods LTR SER and M+LTR SER are not applicable to the NMP2 M+SAR:Methods LTR SER Limitations and Conditions: APPLICATION OF 10 WEIGHT PERCENT GD: Limitation and Condition 9.13MIXED CORE METHOD 1: Limitation and Condition 9.21MIXED CORE METHOD 2: Limitation and Condition 9.22M+LTR SER Limitations and Conditions: CONCURRENT CHANGES: Limitations and Conditions 12.3.d, 12.3.e, and 12.3.fAPPENDIX -A Request for Additional Information (RAI) 14-9: Limitation andCondition 12.23.6APPENDIX -A RAI 14-10: Limitation and Condition 12.23.72.1 FUEL DESIGN AND OPERATION The effect of MELLLA+ on the fuel design and operation is described below. The topicsaddressed in this evaluation are:M+LTRTopic Disposition NMP2 ResultFuel Product Line Design [[Core DesignFuel Thermal Margin Monitoring Threshold ]]2.1.1 Fuel Product LineThe fuel design limits are established for all new fuel product line designs as a part of the fuelintroduction and reload analyses. The M+/-LTR establishes that there are no changes in fuelproduct line design as a consequence of MELLLA+. Because implementation of the MELLLA+operating domain does not necessitate a new fuel design, no additional fuel and core designevaluation is required. NMP2 currently operates with GEl4 fuel. The cycle in which MELLLA+ operating domainexpansion is implemented shall contain GEl4 fuel. [[]] no new fuel product line design is introduced, and there is no change to fueldesign limits required by the MELLLA+ introduction at NMP2. Therefore, the SRLR willconfirm that there are no new fuel products as a result of MELLLA+ and will validate theconclusion that no additional fuel and core design evaluation is required for NMP2.2-1 NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION -CLASS I (PUBLIC)2.1.2 Core Design and Fuel Thermal Monitoring Threshold [[]] the maximum licensed power level and fuel design do not changeas a result of MELLLA+. [[ ]]there is no change to the average power density as a result of MELLLA+ operating domainexpansion. Because the maximum licensed power level and fuel design do not change as a resultof MELLLA+, there is no increase in the average bundle power. Because there is no change inaverage power density, there is no change required to the fuel thermal monitoring threshold. [[ ]] there are no changes to the NMP2fuel or fuel design limits as a result of MELLLA+. NMP2 continues to use GEl4 fuel. TheCLTP remains at 3,988 MWt. This validates the conclusion that there are no changes needed tothe fuel thermal monitoring threshold for NMP2.Furthermore, because the MELLLA+ operating domain allows higher bundle power versus flowconditions, [[ ]] the range of void fraction, axialand radial power shape, and rod positions in the core may change slightly. The change in powerdistribution in the core is achieved, while the individual fuel bundles remain within the allowable thermal limits as defined in the COLR.Also, [[ ]], and per Methods LTR SER Limitation andCondition 9.17, the range of void fraction, axial and radial power shape, and rod positions in thecore does change slightly as a result of MELLLA+ operating domain expansion. For NMP2, thepredicted bypass void fraction at the D-Level local power range monitor (LPRM) satisfied the[[ ]] design requirement. The cycle-specific SRLR will confirm that the void fraction is< 5% according to Methods LTR SER Limitation and Condition 9.17. The table below showsthat steady-state bypass voiding is demonstrated on the MELLLA+ upper boundary at 100%power.% of Rated Core % of Rated Hot Channel Void Fraction in Bypass Region atItemPower Core Flow Instrumentation D Level (ISCOR Node 21)1 100 99 1.6%2 100 85 3.0%As required by Methods LTR SER Limitation and Condition 9.24, the following core design andfuel monitoring parameters are plotted as indicated below in Table 2-1 and Figures 2-1 through2-6 for each cycle exposure statepoint. The parameters are compared to the experience basereported in Reference 3:Table 2-1 Peak Nodal Exposures Figure 2-1 Power of Peak Bundle versus Cycle ExposureFigure 2-2 Coolant Flow for Peak Bundle versus Cycle ExposureFigure 2-3 Exit Void Fraction for Peak Power Bundle versus Cycle Exposure2-2 NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION -CLASS I (PUBLIC)Figure 2-4 Maximum Channel Exit Void Fraction versus Cycle ExposureFigure 2-5 Core Average Exit Void Fraction versus Cycle ExposureFigure 2-6 Peak LHGR versus Cycle ExposureAs part of the information requested for M+LTR SER Limitation and Condition 12.24.2, the exitvoid fraction for peak power bundle versus cycle exposure is provided in Figure 2-3.Also, quarter core maps with mirror symmetry are plotted in Figure 2-7 through Figure 2-15showing bundle power, bundle operating linear heat generation rate (LHGR), and minimumcritical power ratio (MCPR) for beginning of cycle (BOC) (0.2 GWd/ST), middle of cycle(MOC) (10.0 GWd/ST), and end of cycle (EOC) (18.577 GWd/ST). The maximum fraction oflimiting power density (MFLPD) occurs at 15.0 GWd/ST (Figure 2-16) and the largest maximumfraction of limiting critical power ratio (MFLCPR) occurs at 1.5 GWd/ST (Figure 2-17) for thiscore design. In Figure 2-7 through Figure 2-9, the bundle power is dimensionless. To obtain thebundle power in MWt, multiply each number by the average power per bundle. Prior to EOC,the average power per bundle is 5.2199; this factor equals 3,988/764, where 3,988 MWt is theRTP and 764 is the total number of fuel bundles in the core. At EOC, the average power perbundle is 4.6648.Table 2-1 shows that NMP2's Peak Nodal Exposure are lower than the top four reference plants.Figures 2-1 through 2-4 and Figure 2-6 show NMP2 MELLLA+ operation is in the expectedrange as compared to the reference plants. Figure 2-5 shows that NMP2 is higher than all theother plants. This is because of NMP2 MELLLA+ operating conditions, which are at full EPUpower and 85% flow, while the available data for other plants are not at full EPU and/orMELLLA+ conditions. Figures 2-7 through 2-9 show the relative bundle power for BOC, MOC,and EOC, respectively. Figures 2-10 through 2-12 show the operating LHGR for BOC, MOC,and EOC, respectively. Figures 2-13 through 2-15 show the MCPR for BOC, MOC, and EOC,respectively. Figures 2-7 through 2-17 show general operational conditions for NMP2 in theMELLLA+ operating domain are well within expected parameters. 2.2 THERMAL LIMITS ASSESSMENT The effect of MELLLA+ on the MCPR safety and operating limits, maximum average planarlinear heat generation rate (MAPLHGR), and LHGR limits is described below. As required byLimitation and Condition 9.6 of the Methods LTR SER, the GE14 fuel bundle R-factors generated for this project are consistent with GNF standard design practices, which use an axialvoid profile shape with 60% average in-channel voids. This is consistent with lattice axial voidconditions expected for the hot channel operating state as shown in Figure 2-18. As required byMethods LTR SER Limitation and Condition 9.15, the nodal void reactivity biases applied inTRACG are applicable to the lattices representative of fuel loaded in the core.The topics addressed in this evaluation are:2-3 NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION -CLASS I (PUBLIC)Topic M+LTR Disposition NMP2 ResultSafety Limit MCPR Operating Limit MCPRMAPLHGR LimitLHGR Limit 2.2.1 Safety Limit Minimum Critical Power RatioEr]] the SLMCPR is calculated based on the actual coreloading pattern for each reload core. In the event that the cycle-specific SLMCPR is notbounded by the current NMP2 TS value, NMP2 must implement a license amendment to changethe TS.[[ ]] the SLMCPR analysis for NMP2reflects the actual plant core loading pattern and is performed for each reload core. The cycle-specific SLMCPR will be determined using the methods defined in Reference

4. As required byM+LTR SER Limitation and Condition 12.6, the SLMCPR will be calculated at the ratedstatepoint (100% CLTP / 100% CF), the upper right comer of the MELLLA+ upper boundary(100% CLTP / 85% CF), the lower left comer of the MELLLA+ upper boundary (77.6% CLTP /55% CF), and the CLTP at the ICF statepoint (100% CLTP / 105% CF) (i.e., Figure 1-1Statepoints E, N, M, and F, respectively).

See Section 1.2.1 for further information on thepower-to-flow statepoints. The currently approved off-rated CF uncertainty applied to the SLOoperation is used for the minimum CF Statepoint N and at 55.0% CF Statepoint M. Thecalculated values will be documented in the SRLR.As required by Methods LTR SER Limitation and Condition 9.5 and M+LTR SER Limitation and Condition 12.24.3, for MELLLA+ operation, a +0.02 adder will be added to thecycle-specific SLMCPR. The cycle-specific SLMCPR analysis will incorporate the +0.02 adderfor MELLLA+ operation. The calculated values will be documented in the SRLR. A TS changewill be requested if the current value is not bounding. 2.2.2 Operating Limit Minimum Critical Power Ratio]] the OLMCPR is calculated by adding the change inMCPR due to the limiting AOO event to the SLMCPR. [[]] The OLMCPR is determined on a cycle-specific basis from2-4 NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION -CLASS I (PUBLIC)the results of the reload transient

analysis, as described in Reference

4. The cycle-specific analysisresults are documented in the SRLR and included in the COLR. The MELLLA+ operating conditions do not change the methods used to determine this limit.[[ ]] the OLMCPR for NMP2 iscalculated by adding the change in MCPR due to the limiting AOO event to the SLMCPR.]] if the Methods LTR SER and M+LTR SER penalties are ignored for NMP2. The OLMCPR for NMP2 is determined on a cycle-specific basis from theresults of the reload transient

analysis, as described in Reference

4. The NMP2 cycle-specific analysis results are documented in the SRLR and included in the COLR. The MELLLA+operating conditions do not change the methods used to determine this limit. A +0.01 adder willbe applied to the resulting OLMCPR as required by Limitation and Condition 9.19 of theMethods LTR SER. In the event that the cycle-specific reload analysis is based on TRACGrather than ODYN for AOO, no 0.01 adder to the OLMCPR is required.

[[2.2.3 Maximum Average Planar Linear Heat Generation Rate Limits[R ]] MAPLHGR limitsensure that the plant does not exceed regulatory limits established in 10 CFR 50.46. Section 4.3,Emergency Core Cooling System Performance, presents the evaluation to demonstrate that plantsmeet the regulatory limits in the MELLLA+ operating domain. 1Er ]] the NMP2 MAPLHGR limitsensure that NMP2 does not exceed regulatory limits established in 10 CFR 50.46. Section 4.3 ofthis M+SAR presents the evaluation to demonstrate that NMP2 meets the regulatory limits in theMELLLA+ operating domain. [[]] The MELLLA+ operating conditions do not change the methods used to determine this limit.2.2.4 Linear Heat Generation Rate LimitsEr LHGR limits ensure thatthe plant does not exceed fuel thermal-mechanical (T-M) design limits. The LHGR isdetermined by the fuel rod T-M design and is not affected by MELLLA+ operating domainexpansion. No changes to the fuel rod are required as a part of MELLLA+. [[2-5 NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION -CLASS I (PUBLIC)]] the NMP2 LHGR limits ensurethat the plant does not exceed fuel T-M design limits. There are no changes to the NMP2 fuel orfuel design limits as a result of MELLLA+. NMP2 continues to use GEl4 fuel. [[]] The MELLLA+ operating conditions do not change the methods used to determine this limit.[[2.2.5 Power-to-Flow RatioMethods LTR SER Limitation and Condition 9.3 requires that plant-specific EPU and expandedoperating domain applications confirm that the core thermal power to CF ratio does not exceed50 MWt/Mlbm/hr at any statepoint in the allowed operating domain. For plants that exceed thepower-to-flow value of 50 MWt/Mlbmihr, the application will provide a power distribution assessment to establish that axial and nodal power distribution uncertainties determined vianeutronic methods have not increased. The core thermal power to CF ratio at steady-state and off-rated conditions along the MELLLA+boundary is reported in Table 2-2.2.3 REACTIVITY CHARACTERISTICS The effect of MELLLA+ on hot excess reactivity, strong rod out (SRO) shutdown margin, andSLS shutdown margin is described below. The topics addressed in this evaluation are:Topic M+LTR Disposition NMP2 ResultHot Excess Reactivity Strong Rod Out Shutdown MarginSLS Shutdown Margin2.3.1 Hot Excess Reactivity operation in the MELLLA+ operating domain may change the hot excess reactivity during thecycle. This change in reactivity does not affect safety and is not expected to significantly affectthe ability to manage power distribution through the cycle and to achieve the target power level.]] The MELLLA+ operating conditions do notchange the methods used to evaluate hot excess reactivity. 2-6 NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION -CLASS I (PUBLIC)]] NMP2 continues to operate on a 24-month cycle. TheMELLLA+ operating conditions do not change the NMP2 methods used to evaluate thatsufficient hot excess reactivity exists to match the 24 -month cycle conditions. 2.3.2 Strong Rod Out Shutdown Marginhigher core average void fraction results in higher plutonium production, increased hot reactivity later in the operational cycle, and decreased hot-to-cold reactivity differences. Smaller coldshutdown margins may result from cores designed for operation with the MELLLA+ operating domain expansion. This potential loss in margin is offset through core design to maintain currentdesign and TS cold shutdown margin requirements. All minimum SRO shutdown marginrequirements apply to cold most reactive conditions and are maintained without change forMELLLA+ implementation. In order to account for reactivity uncertainties, including the effectsof temperature and analysis

methods, margin well in excess of the TS limits is included in thedesign requirements.

[[The MELLLA+ operating conditions do not change the methods used to evaluate SRO shutdownmargin.I NMP2 current design and TS cold shutdown marginlimits are unchanged by MELLLA+. The MELLLA+ operating conditions do not change theNMP2 methods used to evaluate that SRO shutdown margin meets the current NMP2 design andTS cold shutdown limits.2.3.3 SLS Shutdown Margin]] higher core average void fraction results in higher plutonium production, increased hot reactivity later in the operational cycle, and decreased hot-to-cold reactivity differences. Smaller cold shutdown margins may result from cores designed for operation with the MELLLA+ operating domain expansion. This potential loss in margin is offset throughcore design to maintain current design and SLS TS requirements. All minimum SLS TSrequirements apply to most reactive SLS conditions and are maintained without change forMELLLA+ implementation. In order to account for reactivity uncertainties, including the effectsof temperature and analysis

methods, margin in excess of the TS limits is included in the design2-7 NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION

-CLASS I (PUBLIC)requirements. [[]] The MELLLA+operating conditions do not change the methods used to evaluate the SLS shutdown margin.i NMP2 current design and SLS TS requirements for minimumnatural boron equivalent are unchanged by the SLS performance modification or MELLLA+.The MELLLA+ operating conditions do not change the NMP2 methods used to evaluate thatSLS shutdown margin meets the current NMP2 design and SLS TS requirements. The SLSperformance modifications are to increase the boron injection rate to support ATWS evaluations and do not affect the SLS shutdown margin evaluation.

2.4 STABILITY

The DSS-CD stability solution (Reference

2) has been shown to provide an early trip signal uponinstability inception prior to any significant oscillation amplitude growth and MCPR degradation for both core-wide and regional mode oscillations.

NMP2 will implement the DSS-CD solutionconsistent with the M+LTR. DSS-CD implementation includes any limitations and conditions inthe DSS-CD SER (Reference 2). In accordance with DSS-CD LTR SER Limitation andCondition 5.1 (Reference 2), because NMP2 is implementing DSS-CD using the NRC approvedGEH Option III platform, a plant-specific review is not required. There were no changesproposed in the bounding uncertainty or in the process to bound the uncertainty in the MCPR.Topic M+LTR Disposition NMP2 ResultDSS-CD Setpoints Armed RegionBackup Stability Protection (BSP) 2.4.1 DSS-CD Setpoints ]] As a part of DSS-CD implementation, the applicability checklist is incorporated into the reload evaluation process and is documented in the SRLR.DSS-CD implementation also includes incorporation of appropriate [[ ]] analysesto be performed if a specific reload analysis [[]] DSS-CD is incorporated per the requirements of the DSS-CDLTR. This implementation requires that a process for reviewing the DSS-CD setpoints for eachreload analysis is in place. [[2-8 NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION -CLASS I (PUBLIC)]] no further review of MELLLA+ isnecessary to evaluate the adequacy of the DSS-CD setpoints. [[ ]] NMP2 will incorporate theDSS-CD solution consistent with the requirements of the DSS-CD LTR. Implementation ofDSS-CD in accordance with the DSS-CD LTR ensures that NMP2 incorporates the applicability checklist into the reload evaluation process and documents the results of the applicability checklist review in the SRLR. DSS-CD implementation per the DSS-CD LTR also ensures thatNMP2 incorporates appropriate [[ ]] analyses to be performed if a specific reloadanalysis [[The generic DSS-CD licensing basis applicable to NMP2 is documented in Section 4.7 ofReference

2. [[]] The step-by-step process summary for DSS-CD application of higher amplitude discriminator setpoint (SAD) is detailed in Table 4-17 of Reference

2. The results of theapplication of this process to NMP2 are summarized below.[[2-9 NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION

-CLASS I (PUBLIC)2-10 NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION -CLASS I (PUBLIC)]]The CDA setpoint calculation formula and the adjustable parameter values are defined in theDSS-CD LTR (Reference 2). In accordance with DSS-CD LTR SER Limitation andCondition 5.2 (Reference 2), the DSS-CD LTR, or GESTAR II including the approved DSS-CDLTR, is referenced in the proposed TS changes for implementation of DSS-CD.2.4.2 Armed Region2-11 NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION -CLASS I (PUBLIC)]]The generic boundaries of the armed region were approved as part of the DSS-CD LTR.[[]] no further review of MELLLA+ is necessary to evaluate the adequacyof the armed region.Erno further review of MELLLA+ is necessary to evaluate the adequacy of the armedregion.Er2.4.3 Backup Stability Protection Er ]] the DSS-CD LTRdefines the BSP along with a generic process for confirming that the BSP requirements are metin each reload analysis. This BSP may be used when the OPRM system is temporarily inoperable. Implementation of DSS-CD per the DSS-CD LTR requires that the alternate stability protection approach is confirmed on a cycle-specific basis to demonstrate adequacy for eachreload cycle. no further review of MELLLA+ is necessary to evaluatethe adequacy of the BSP.Er NMP2 will incorporate theDSS-CD solution in accordance with the requirements of the DSS-CD LTR. Implementation ofDSS-CD in accordance with the DSS-CD LTR requires that NMP2 confirm the BSP approach isadequate as a part of the reload. [[]] no further review of BSP is required. Er2-12 NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION -CLASS I (PUBLIC)2-13 NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION -CLASS I (PUBLIC)2.5 REACTIVITY CONTROLThe control rod drive (CRD) system controls core reactivity by positioning neutron absorbing control rods within the reactor and scram the reactor by rapidly inserting control rods into thecore. No change is made to the control rods or drive system due to MELLLA+. The topicsaddressed in this evaluation are:Topic M+LTR Disposition NMP2 ResultScram Time ResponseCRD Positioning and CoolingCRD Integrity 2.5.1 Control Rod Scram[ ]]forBWR/3, BWR/4, and BWR/5 plants the hydraulic control unit accumulators supply the initialscram pressure and, as the scram continues, the reactor becomes the primary source of pressureto complete the scram.]] the NMP2 hydraulic control unitaccumulators supply the initial scram pressure and, as the scram continues, the reactor becomesthe primary source of pressure to complete the scram. The NMP2 reactor dome pressure is1,035 psia (1,020 psig) and does not change as a result of MELLLA+ operating domainexpansion. [[2.5.2 Control Rod Drive Positioning and CoolingI As a result ofMELLLA+, there is no increase in temperature and [[]] Therefore, the CRD positioning and cooling functions are not affected byMELLLA+.[[ ]] for NMP2, the reactor coolanttemperature does not increase. [[2-14 NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION -CLASS I (PUBLIC)2.5.3 Control Rod Drive Integrity []] thepostulated abnormal operating conditions for the CRD design assume a failure of the CRDsystem pressure-regulating valve that applies the maximum pump discharge pressure to the CRDmechanism internal components. This postulated abnormal pressure bounds the AmericanSociety of Mechanical Engineers (ASME) reactor overpressure limit. no further evaluation of CRD integrity is requiredas result of MELLLA+.ER the NMP2 CRD mechanism hasbeen analyzed for an abnormal pressure operation (the application of the maximum CRD pumpdischarge pressure) that bounds the ASME RPV overpressure condition. [[]] Also, as stated inSection 3.1.2, for the ASME RPV overpressure condition, the peak RPV bottom head pressure isunchanged and remains less than the limit of 1,375 psig. [[]] and no further evaluation of CRD integrity is required as result of MELLLA+.Er2.6 ADDITIONAL LIMITATIONS AND CONDITIONS RELATED TO REACTOR CORE AND FUELPERFORMANCE For that subset of limitations and conditions relating to Reactor Core and Fuel Design, which didnot fit conveniently into the organizational structure of the M+LTR, the required information ispresented here. The information is identified by either the M+LTR SER (Reference

1) limitation and condition or the Methods LTR SER (Reference

3) limitation and condition to which itrelates.2.6.1 TGBLA/PANAC VersionIn developing the NMP2 equilibrium core, the latest versions of TGBLA and PANAC were used.Refer to Table 1-1 for the latest revisions to TGBLA and PANAC. Cycle-specific analyses willinclude the most recent TGBLA and PANAC versions.

As required by Methods LTR SERLimitation and Condition 9.1, the most recent versions of TGBLA and PANAC are used.2.6.2 M+LTR SER Limitation and Condition 12.24.12-15 NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION -CLASS I (PUBLIC)2.6.3 LHGR and Exposure Qualification Methods LTR SER Limitation and Condition 9.12 states that once the PRIME LTR(Reference

15) and its application are approved, future license applications for EPU andMELLLA+ referencing LTR NEDC-33173P-A must utilize the PRIME T-M methods.

ThePRIME LTR was approved on January 22, 2010 (Reference

15) and implemented in GESTAR IIin September 2010 (Reference 4). The NMP2 M+SAR has a PRIME T-M basis. PRIME fuelparameters have been used in all analyses requiring fuel performance parameters.

The T-M evaluation performed in support of the NMP2 M+SAR was performed using thePRIME T-M methodology. 2.6.4 GEXL-PLUS and Pressure Drop DatabaseThe applicability of the GE14 experimental GEXL-PLUS and pressure drop database isconfirmed for operation in the MELLLA+ domain.The Methods LTR NEDC-33173P-A (Reference

3) documents all analyses supporting theconclusions in this section that the application ranges of GEH codes and methods are adequate inthe MELLLA+ operating domain. In accordance with M+LTR SER Limitation andCondition 12.1, the range of mass fluxes and power/flow ratios in the GEXL database covers theintended MELLLA+ operating domain. The database includes low flow, high qualities, and voidfractions.

There are no restrictions on the application of the GEXL-PLUS correlation in theMELLLA+ operating domain.2-16 NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION -CLASS I (PUBLIC)Table 2-1 Peak Nodal Exposures Peak Nodal ExposurePlant Cycle (~IT(GWd/ST)A 18 38.849A 19 43.784B 9 56.359B 10 51.544C 7 53.447C 8 47.766D 13 56.660E 11 55.387F EQ- 120% 51.174NMP2 MELLLA+ 52.0032-17 NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION -CLASS I (PUBLIC)Table 2-2 Core Thermal Power to Core Flow Ratio at Steady-State andOff-Rated Conditions Operating Domain Core Thermal Power Core Flow Power-to-Flow RatioStatepoint* (MWt / %EPU) (Mlbm/hr / %rated) (MWt/MlbmI/hr) M/M+ Boundary "D" 3,988/100 107.4/99 37.13M+ Boundary "N" 3,988 / 100 92.2 / 85 43.24M+ Boundary "M" 3,095 / 77.6 59.7/55 51.86M/M+ Boundary "L" 2,727.8 / 68.4 59.7 / 55 45.71"*" Statepoints D, N, M, and L are shown in Figure 1-1.2-18 NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION -CLASS I (PUBLIC)Table 2-3 TLO and SLO DSS-CD Licensing Basis Generic Applicability EnvelopeChecklist Confirmation 2-19 NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION -CLASS I (PUBLIC)Table 2-4 [111Note: [[2-20 NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION -CLASS I (PUBLIC)Table 2-5 [111Note: [[2-21 NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION -CLASS I (PUBLIC)8.07.5 '7 .0 -- ---- ----------'6.55.5--*-Plant A Cycle 18 m-Plant A Cycle 19 --.-Plant B Cycle 94.5 -o PlantBCyclelO 1 Plant C Cycle 7 --PlantCCydeB -*-Plant D Cycle13 -PlantECyclell -PlantF4.0, -*-NMP2 M ELLLA+0 2 4 6 8 10 12 14 16 18Cycle Exposure (GWDYST)Figure 2-1 Power of Peak Bundle versus Cycle Exposure2-22 NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION -CLASS I (PUBLIC)1413~12E-6119)71-*-PlantA Cycle18 ---PlantA Cycle 19 -PlantB Cycle 9-4Plant B Cycle 10 -Plant C Cycle 7 -Plant C Cycle 8-PlantDCycle13 -PlantE Cycle 11 PPlantF-.--NM P2 M ELLLA+50 2 4 6 8 10 12Cycle Exposure (GWDIST)14 16 18Figure 2-2 Coolant Flow for Peak Bundle versus Cycle Exposure2-23 NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION -CLASS I (PUBLIC)0.900.85W0.LL".0;0.75 -0.70-Plant A Cycle 18 --U- PlantA Cycle 19 ý-Plant B Cycle 9-Plant B Cycle 10 --PlantC Cycle 7 Plant C Cycle 8-Plant D Cycle 13 -PlantE Cycle 11 -Plant F--4-NMP2 MELLLA+I-0 2 4 6 8 10 12Cycle Exposure (GWDWS-)14 16 18Figure 2-3Exit Void Fraction for Peak Power Bundle versus Cycle Exposure2-24 NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION -CLASS I (PUBLIC)0.900.85.X 0.85I-Lo.N0.750.70---Plant A Cycle 18-4Plant B Cycle 10--Plant D Cyclel3--NMP2 MELLLA+-u--Plant A Cycle 19-.--Plant C Cycle 7-Plant E Cycle 110 2 4 6 8 10 12Cycle Exposure (GWD/ST)14 16 18Figure 2-4Maximum Channel Exit Void Fraction versus Cycle Exposure2-25 NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION -CLASS I (PUBLIC)t;L-49XUj=4)00,00.800.780.760.740.720.700.680.660.640.620.60--- -------- -------- --- --------------------- IN------------- 4 --------

--- ---------

--PlantA Cycle 18---PlantB Cycle 10PlantD Cycle 13--NMP2 MELLLA+-4w- Plant A Cycle 19-o-Plant C Cycle 7-Plant E Cycle 110 2 4 6 8 10 12Cycle Exposure (GWDIST)14 16 18Figure 2-5 Core Average Exit Void Fraction versus Cycle Exposure2-26 NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION -CLASS I (PUBLIC)161412,=I------------------------

4.2-* PlantA Cycle 18 -PlantA Cycle 19* lPlantBCycle10

-PlantC Cycle7-Plant D Cycle 13 -Plant C Cycle 11---NM P2 M ELLLA+---Plant B Cycle 9Plant C Cycle 8-Plant FL ]00 2 4 6 8 10 12Cycle Exposure (GWDP'ST) 14 16 18Figure 2-6 Peak LHGR versus Cycle Exposure2-27 NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION -CLASS I (PUBLIC)ab lob go- U*Imon ---------- jW4=9 ! "FlM Fs f W2 3 , S , 1 1 , .t iQ 0 14Figure 2-7 Dimensionless Bundle Power at BOC (200 MWd/ST)2-28 NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION -CLASS I (PUBLIC)Sm -t~p~m -,no u-I"ab imI~,r-,TiNcoma POWILf-WRX" $

7 I S U 5 1U00d¶ M T~Figure 2-8 Dimensionless Bundle Power at MOC (10,000 MWd/ST)2-29 NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION

-CLASS I (PUBLIC)@doWWWAPWcW00l2 46MSt0my Mof, i-j,o *as...4.. G ..I.. .; .!...Figure 2-9 Dimensionless Bundle Power at EOC (18,577 MWd/ST)2-30 NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION -CLASS I (PUBLIC)mlllit,_= ' ., IDow-*-- Oft:--IKY _j 4 $

I 40mm- _4- F. M..............

s O F1: 1 17"Figure 2-10 Bundle Operating LHGR (kW/ft) at BOC (200 MWd/ST)2-31 NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION -CLASS I (PUBLIC)go 1***0- toPcW _jtpu I'""'I*61

iF i ur 4 B d I $
atU M 0 4I UISTFigure 2-11 Bundle Operating LHGR (kW/ft) at MOC (10,000 MWd/ST)2-32 NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION

-CLASS I (PUBLIC)F3os in Qfm -t6 NNm Sm rvzo" 2s P-0b.~ ~ ,Figure 2-12 Bundle Operating LHGR (kW/ft) at EOC (18,577 MWd/ST)2-33 NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION -CLASS I (PUBLIC)Ai';,'A-.'ý ! -' PRAI " ...j 2rub. oo, nm*rCTP 22comecwlow I [toit1Figure 2-13 Bundle Operating MCPR at BOC (200 MWd/ST)2-34 NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION -CLASS I (PUBLIC)FOO F- Fof :,_. -.FrLWAG(.00"i 2sFnnMT Vcow1I 2 ) 4 I.

2 1 I
11 U 1j~b~isd" MVM NoFigure 2-14 Bundle Operating MCPR at MOC (10,000 MWd/ST)2-35 NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION

-CLASS I (PUBLIC)"eine mmoCAIJT09'4.. ... ...... .. V'QolwmIM21*1I 2 s 4 s

7 1 0 S z 1 1 4 isFigure 2-15 Bundle Operating MCPR at EOC (18,577 MWd/ST)2-36 NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION

-CLASS I (PUBLIC)I AVAIXIUý' I I'.' FqrF___ mPcTV _- 4 As-L"u 'Il FEW mFKfur'izmm m ,Fo--n*m-,-F-m-F mi 2 B O4W 1E00 WMM1 3 S 4 6 I S I I U It 12 is 14 IFigure 2-16 Bundle Operating LHGR (kW/ft) at 15,000 MWdIST (Peak MFLPD Point)2-37 NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION -CLASS I (PUBLIC)[ AFAIA-11,' I I'.' pqr__ý F3OR1- m 1d094"how I 2 9S13FA:_1IViFigure 2-17 Bundle Operating MCPR at 1,500 MWd/ST (Peak MFLCPR Point)2-38 NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION -CLASS I (PUBLIC)viil a11w l Ilio1111so IIUIII~3E~ruU~I*IhhIII~~huIIUIflhIIII~u~lhEIUI~t2 -c ZItef 1111111ol 1111f:fi9sl vies 1:a411 u4 olil UipolFigure 2-18 Bundle Average Void History for Bundles with Low CPRs2-39 NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION -CLASS I (PUBLIC)Core Flow (Mlbm/hr) 0 10 20 30 40 50 60 70 80 90 100 110 120130120110100908070600 50403020100OPRM Armed Region------ .. ... --------..... The OPRM Armed Region is* defined by 75% drive flow. ."However the use of 75% coreflow is conservaive .450040003500300025002000150010005000T.. 7-__0 10 20 30 40 50 60 70 80 90 100 110Core Flow (%)120Figure 2-19 Required OPRM Armed Region2-40 NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION -CLASS I (PUBLIC)3.0 REACTOR COOLANT AND CONNECTED SYSTEMSThis section addresses the evaluations that are applicable to MELLLA+.3.1 NUCLEAR SYSTEM PRESSURE RELIEF AND OVERPRESSURE PROTECTION The topics addressed in this evaluation are:Topic M+LTR Disposition NMP2 ResultFlow-Induced Vibration i[Overpressure Relief Capacity3.1.1 Flow-Induced Vibration because there is no increase in the maximum main steam (MS) line flow for the MELLLA+operating domain expansion, there is no effect on the flow-induced vibration (FIV) of the pipingand SRVs during normal operation. [[]] for NMP2, maximum MS line(MSL) flow in the MELLLA+ operating domain does not increase. The numerical valuesshowing no increase in maximum steam flow rate are presented in Table 1-2. MELLLA+ doesnot result in any increase to the NMP2 maximum MSL flow, and there is no effect on the FIVexperienced by the SRVs or piping during normal operation. [[I]3.1.2 Overpressure Relief CapacityThe pressure relief system prevents overpressurization of the nuclear system during AOOs, theplant ASME upset overpressure protection event, and postulated ATWS events. The SRVsalong with other functions provide this protection. For NMP2, the limiting overpressure event isthe main steam isolation valve closure with scram on high flux (MSIVF) event. The peak RPVbottom head pressure is unchanged and remains less than the ASME limit of 1,375 psig.The SRV setpoint tolerance is independent of the MELLLA+ operating domain expansion. TheAOO, ASME overpressure, and ATWS response evaluations for MELLLA+ are performed usingexisting NMP2 SRV setpoint tolerances. The SRV setpoint tolerances are monitored at NMP2for compliance to the TS requirements. ]] Thereare no changes made to the NMP2 licensing basis for the ASME overpressure event.]] The SRV tolerance assumed in the NMP2 ASME overpressure event3-1 NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION -CLASS I (PUBLIC)analysis is 3%. The tolerance is consistent with the actual SRV performance testing conducted on the NMP2 SRVs per TS Surveillance Requirement 3.4.4.1.Er]] There are no changes to theexisting licensing basis assumptions and code inputs used for the NMP2 ASME overpressure event analysis. The ASME overpressure analysis for NMP2 was performed at the 105% ICF core flowstatepoint, and at the 85% minimum CF statepoint using an approximate MELLLA+ equilibrium core. The analysis of the limiting overpressure event for NMP2 demonstrates that no change inoverpressure relief capacity is required. [[]] This process is unchanged by MELLLA+.3.2 REACTOR VESSELThe RPV structure and support components form a pressure boundary to contain reactor coolantand form a boundary against leakage of radioactive materials into the drywell (DW). The topicsaddressed in this evaluation are:Topic M+LTR Disposition NMP2 ResultFracture Toughness Reactor Vessel Structural Evaluation 3.2.1 Fracture Toughness The MELLLA+ operating domain expansion results in a slightly higher operating neutron flux inthe upper portion of the core due to decreased water density. The effect of this water densityreduction is [[ ]] in peak vessel and peak shroud flux. Inaccordance with M+LTR SER Limitation and Condition 12.8, the MELLLA+ flux is calculated using the GEH flux evaluation methodology contained in NEDC-32983P-A (Reference 16),which is consistent with Regulatory Guide (RG) 1.190 (Reference

17) and was approved by theNRC in November 2005. The evaluation is based on an idealized equilibrium core loadingwhich is not a bounding core design. This core loading is intended to show general trends for thepurpose of comparison and demonstrating the anticipated effect on flux and fluence.

The NMP2RG 1.190 (Reference

17) fluence program monitors actual core operations to determine theeffect on fracture toughness.

The MELLLA+ operating domain flux distribution is assumed tobe similar to that of current licensed operating domain flux distribution, whereas the magnitude of flux level is proportional to the thermal power. The change to the NMP2 54 effective fullpower years (EFPYs) vessel internal diameter (ID) peak fluence as a result of implementing MELLLA+ is [[ 1]Key flux/fluence comparisons at 120% OLTP are provided in Table 3-1.Because there is no change to the NMP2 54 EFPY Vessel ID peak fluence as a result ofMELLLA+, there is no change to the beltline adjusted reference temperature (ART). The3-2 NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION -CLASS I (PUBLIC)pressure/temperature curves do not require revision as a result of MELLLA+ operating domainexpansion. Because there is no change to the NMP2 54 EFPY Vessel ID peak fluence as a result ofMELLLA+, there is no change to the upper shelf energy (USE). NMP2 continues to meet the50 ft-lb requirement in 10 CFR 50, Appendix GBecause there is no change to the NMP2 54 EFPY Vessel ID peak fluence as a result ofMELLLA+, there is no change to the Weld Inspection Relief criteria for circumferential welds.Therefore, the inspection relief request does not require revision as a result of MELLLA+operating domain expansion. As a result of MELLLA+ there is no change in the NMP2 54 EFPY Vessel ID peak fluence.Therefore, there are no changes to the NMP2 ART, USE, or Weld inspection relief values as aresult of MELLLA+.3.2.2 Reactor Vessel Structural Evaluation [[]] there are no changes in the reactor operating

pressure, FW flow rate, or steamflow rates for the MELLLA+ operating domain expansion.

Other applicable mechanical loadsdo not increase for the MELLLA+ operating domain expansion. [[]] there is no change in the stress or fatigue for thereactor vessel components as a result of MELLLA+, and no further evaluation is required. [[ ]] for NMP2, there are no increases in the reactor operating

pressure, or maximum steam or FW flow rates for the MELLLA+operating domain expansion.

The numerical values showing no increases in reactor operating

pressure, or maximum steam or FW flow rates are presented in Table 1-2. Other NMP2mechanical loads do not increase as a result of the MELLLA+ operating domain expansion.

Therefore, there is no change in the stress and fatigue for the NMP2 reactor vessel components, and no further evaluation of NMP2 reactor vessel structural integrity is required. 3.3 REACTOR INTERNALS 3.3.1 Reactor Internal Pressure Differences The reactor internals include core support structure and non-core support structure components. The topics addressed in this evaluation are:3-3 NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION -CLASS I (PUBLIC)M+LTRTopic Disposition NMP2 ResultFuel Assembly and Control Rod Guide Tube Lift Forces [[Reactor Internal Pressure Differences for Normal, Upset,Emergency and Faulted Conditions Reactor Internal Pressure Differences (Acoustic andFlow-Induced Loads) for Faulted Conditions Reactor Internals Structural Evaluation for Normal,Upset, and Emergency Conditions Reactor Internals Structural Evaluation for FaultedConditions Steam Dryer Separator Performance Steam Line Moisture Performance Specification ]]3.3.1.1 Fuel Assembly and Control Rod Guide Tube Lift Forces]] fuel assembly and CRGT lift forces are calculated for normal, upset, emergency, and faulted conditions consistent with the existing plant designbasis. There are no increases in the core exit steam flow, reactor operating

pressure, FW orsteam flow rates for the MELLLA+ operating domain expansion.

Because none of the preceding values change, the only remaining variable affecting the forces on the fuel assemblies andCRGTs for the normal, upset, emergency and faulted conditions in the MELLLA+ operating domain is the CF. Maximum CF is reduced in the MELLLA+ operating domain. [[]] Therefore, no further evaluation of fuel assembly or CRGT lift forces isrequired. [[ ]] for NMP2, the difference betweenthe 100% CLTP / 105% core flow ICF operation point core exit steam flow and the 100% CLTP/ 85% core flow MELLLA+ operation point core exit steam flow is essentially unchanged (lessthan a 0.4% increase). The differences between the vessel steam flow and FW flow rates for thetwo power-flow points are essentially unchanged, as well (both less than a 0.2% decrease). Thedome pressures for the two power-flow points are identical. The small differences between thecore exit steam flows, vessel steam flows and FW flow rates have a negligible effect on the fuelassembly and CRGT lift forces calculated for normal, upset, emergency and faulted conditions. Therefore, because the NMP2 CF at the MELLLA+ statepoint at 85% CF is less than the currentlicensed operating domain statepoint at 105% CF, the normal, upset, emergency and faulted fuelassembly and CRGT lift forces for the MELLLA+ operating domain [[3-4 NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION -CLASS I (PUBLIC)]] and no further evaluation of these forces is required. I]3.3.1.2 Reactor Internal Pressure Differences for Normal, Upset, Emergency and FaultedConditions [[]] RIPDs (pressure differentials across the components) arecalculated for normal, upset, emergency and faulted conditions consistent with the existing plantdesign basis. There are essentially no changes in the core exit steam flow, reactor operating

pressure, FW or steam flow rates for the MELLLA+ operating domain expansion.

Because noneof the preceding values change, the only remaining variable affecting the RIPDs for the normal,upset, emergency and faulted conditions in the MELLLA+ operating domain is the CF.Maximum CF is reduced in the MELLLA+ operating domain. [[]] Therefore, no further evaluation of RIPDs for normal,upset, emergency and faulted conditions is required. [[ ]] for NMP2, the difference betweenthe 100% CLTP / 105% core flow ICF operation point core exit steam flow and the 100% CLTP/ 85% core flow MELLLA+ operation point core exit steam flow is less than a 0.4% increase. The differences between the vessel steam flow and FW flow rates for the two power-flow pointsare both less than a 0.2% decrease. The dome pressures for the two power-flow points areidentical. The small differences between the core exit steam flows, vessel steam flows and FWflow rates have a negligible effect on the RIPDs for normal, upset, emergency and faultedconditions. Therefore, because the NMP2 CF at the MELLLA+ statepoint at 85% CF is lessthan the current licensed operating domain statepoint at 105% CF, the normal, upset, emergency and faulted condition RIPDs for the MELLLA+ operating domain [[]] which includes ICF up to 105% RCF.]] and no further evaluation of thesepressure differentials is required for normal, upset, emergency and faulted conditions. 3.3.1.3 Reactor Internal Pressure Differences (Acoustic and Flow-Induced Loads) forFaulted Conditions As part of the RIPDs, the faulted acoustic and flow induced loads in the RPV annulus on jetpump, core shroud and core shroud support resulting from the recirculation line break LOCAhave been considered in the NMP2 evaluation. [[3-5 NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION -CLASS I (PUBLIC)]] and NMP2 R[PDs for faulted conditions continueto be acceptable. [[3.3.2 Reactor Internals Structural Evaluation Structural integrity evaluations for MELLLA+ operating domain expansion are performed consistent with the existing design basis of the components. [[]] Therefore, no further structural evaluation of the reactor internals isrequired. An evaluation of the load categories applicable to the reactor internals under normal,upset, and emergency conditions is presented below:MELLLA+ ResultsLoad Category for Normal, Upset and Emergency Conditions Dead WeightSeismic (Operating BasisEarthquake (OBE))RIPDsFuel Assembly and CRGT LiftForcesContainment Dynamic Loads -(LOCA and SRV)Fuel Lift LoadsThermal Effects3-6 NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION -CLASS I (PUBLIC)MELLLA+ ResultsLoad Category for Normal, Upset and Emergency Conditions Flow[[3.3.2.1 Reactor Internals Structural Evaluation for Faulted Conditions ]] The M+LTRalso defines that if the load conditions do not increase in the MELLLA+ operating domain, thenthe existing analysis results are bounding and no further evaluation is required. Applicable loads, load combinations, and service conditions are evaluated consistent with the plant designbasis for each component. As shown below, [[]] and thus no further evaluation is required. MELLLA+ ResultsLoad Category for Faulted Conditions Dead WeightSeismic (Safe ShutdownEarthquake (SSE))RIPDsFuel Assembly and CRGT LiftForcesContainment Dynamic Loads -(LOCA and SRV)Annulus Pressurization Jet ReactionFuel Lift LoadsFlowAcoustic and Flow-Induced LoadsDue To Recirculation Line Break3-7 NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION -CLASS I (PUBLIC)The faulted condition loads for the NMP2 reactor internal components resulting from theMELLLA+ operating domain conditions [[1] no further evaluation for Reactor Internals Structural Evaluation for faulted conditions is required. 3.3.3 Steam Separator and Dryer Performance The performance of the NMP2 steam separator-dryer has been evaluated to determine themoisture content of the steam leaving the RPV. Compared to the current licensed operating domain (100% CF statepoint), the average separator inlet flow decreases and the averageseparator inlet quality increases at MELLLA+ conditions. These factors, in addition to the coreradial power distribution, affect the steam separator-dryer performance. Steam separator-dryer performance was evaluated at equilibrium cycle limiting conditions of high radial power peakingand 85% RCF to assess their capability to provide the quality of steam necessary to meetoperational criteria at MELLLA+ operating conditions. The evaluation of steam separator and dryer performance indicates that MCO increases atMELLLA+ conditions. This increase resulted in a MCO value above the original moistureperformance specification of 0.10 wt.%. Section 3.3.4 identifies a plant-specific moistureperformance specification based on as installed hardware. 3.3.4 Steam Line Moisture Performance Specification The effect of increased MCO on plant operation has been analyzed to verify acceptable steamseparator-dryer performance under MELLLA+ operating conditions for a maximum moisturecontent of 0.25 wt.%. MCO is monitored during operation to ensure adequate operating limitations are implemented as required to maintain MCO within analyzed conditions. Theamount of time NMP2 is operated with higher than the original design moisture content(0.10 wt.%) is minimized by operations. MCO monitoring periodicity is based upon results ofstartup testing, operating experience, control rod pattern and time in core life.The ability of the steam dryer and separator to perform their design functions during MELLLA+operation was evaluated. The NMP2 plant-specific evaluation concluded that the performance ofthe steam dryer and separator remains acceptable and the dryer skirt remains covered at L4, thelow water level alarm in the MELLLA+ region.MELLLA+ operation decreases the CF rate, resulting in an increase in separator inlet quality forconstant reactor thermal power. These factors, in addition to core radial power distribution, influence steam separator-dryer performance. NMP2's steam separator/dryer performance wasevaluated on a plant-specific basis to determine the influence of MELLLA+ on the steam dryerand separator operating conditions: (1) the entrained steam (i.e., carryunder) in the waterreturning from the separators to the reactor annulus region; (2) the moisture content in the steamleaving the RPV into the MSLs; and (3) the margin to dryer skirt uncovery. 3-8 NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION -CLASS I (PUBLIC)The moisture content of the steam leaving the RPV increases in the MELLLA+ domain. Theeffect of the increase has been analyzed in the tasks that use the MCO value from Sections 3.3.3and 3.3.4. The effects of increased moisture are discussed in the following sections:

a. 3.5.1 Reactor Coolant Pressure Boundary Piping[R 1] as discussed inSection 3.3.3, the MCO may increase during the cycle when a plant is operating at ornear the MELLLA+ minimum CF rate.R[ ]] the MCO for NMP2 may increase to amaximum of 0.25 wt.% during the cycle when NMP2 is operating at or near theMELLLA+ minimum CF rate.b. 8.1 Liquid and Solid Waste Management Although the volume of waste generated is not expected to increase, potentially higherMCO in the reactor steam would result in a slightly higher loading on the condensate demineralizers.

Because the higher moisture content will occur infrequently, theMELLLA+ operating domain expansion will not cause the condensate demineralizer backwash frequency to be changed significantly as discussed in Section 8.1.2. Thereactor water cleanup (RWCU) filter demineralizer backwash frequency is not affectedbecause there is no effect on RWCU inlet conditions for MELLLA+, as discussed inSection 3.11.c. 8.4.2 Fission and Activation Corrosion ProductsSteam separator and dryer performance for MELLLA+ operation is discussed inSection 3.3.3. The moisture content of the MS leaving the vessel may increase up to0.25 wt.% at times while operating near the minimum CF in the MELLLA+ operating domain. The distribution of the fission and activated corrosion product activity betweenthe reactor water and steam is affected by the increased moisture content. With increased MCO, additional activity is carried over from the reactor water with the steam. Themaximum allowable moisture content leaving the reactor vessel is 0.25 wt.%.d. 8.5 Radiation LevelsAs discussed in Section 8.4, the moisture content of the MS leaving the vessel mayincrease at certain times while operating in the MELLLA+ operating domain. However,the NMP2 MCO will be monitored and controlled to < 0.25 wt.%, which is within theanalytical assumption of 0.35 wt.% used in the determination of normal operation radiation levels. The overall radiological effect of the increased moisture content is afunction of the plant water radiochemistry and the levels of activated corrosion productsmaintained.

e. 10.7.2 Flow Accelerated Corrosion The EPU flow accelerated corrosion (FAC) evaluation for MS and extraction steampiping assumed a 0.25 wt.% MCO for mechanical thermal conditions.

This 0.25 wt.%3-9 NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION -CLASS I (PUBLIC)MCO value bounds the maximum predicted MCO value of 0.236 wt.% for MELLLA+based on equilibrium fuel cycle burnup assumptions. The predicted MCO is a function offuel loading and rod patterns throughout the burnup history. The MSIVs allowable moisture content was found to be acceptable for MELLLA+ operation based on GEHengineering

judgment, operating experience, and NMP2's MSIV inspection/maintenance program.

The increased moisture content will not create a significant change in wear onMS piping and components based on the evaluations performed using CHECWORKSTM and design assessments for the components. MCO will be managed with monitoring toidentify and track the duration of MCO above 0.1 wt.% based on taking chemicalsamples once per month. The FAC monitoring program was reviewed for potential changes to the program. No changes to the FAC program are required. The FAC relatedpiping and component wear is managed by the FAC program and Maintenance Rule asdiscussed in Section 10.7.2.f. 5.2.4 Main Steam Flow -FW Flow MismatchOperation at the higher MCO performance specification is acceptable. With a dryermoisture performance specification up to 0.35 wt.%, the additional coolant removed fromthe RPV must be returned to the reactor in order to maintain correct water level. The FWsystem may be required to provide a slightly higher flow rate. The effect of the increased MSL MCO is to cause a slight imbalance in the FW control system control point. With aplant bias of 0.48 inches per percent this translates to z 0.12 inches of bias in the waterlevel.g 3.4.1 Piping Components with Flow-Induced Vibration -Safety RelatedAdequate margin exists to the FIV of the sample probes and thermowells due to the largemargin available in the design.3.4 FLOW-INDUCED VIBRATION The FIV evaluation addresses the influence of the MELLLA+ operating domain expansion onreactor coolant pressure boundary (RCPB) piping, RCPB piping components, and RPV internals. The topics addressed in this evaluation are:Topic M+LTR Disposition NMP2 ResultPiping FIV Evaluation Recirculation System PipingMain Steam PipingFeedwater PipingSafety-Related Thermowells and ProbesRPV Internals FIV Evaluation 3.4.1 FIV Influence on Piping]] Flow rates in the recirculation system3-10 NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION -CLASS I (PUBLIC)piping, MS piping, and FW piping as well as associated MS and FW branch lines do not increaseas a result of MELLLA+ operating domain expansion. [[]] and no further evaluation of FIV influence on recirculation, MS,and FW piping is required. ]] For NMP2, there are noincreases in the recirculation system, MS, or FW flow rates as a result of MELLLA+ operating domain expansion as compared to the current licensed operating domain. The numerical valuesshowing no increases in recirculation system, MS, or FW flow rates are presented in Table 1-2.]] and no further evaluation ofFIV influence on recirculation, MS, and FW piping is required. ]] Because the flow rates inthese piping systems do not increase for MELLLA+, there is no increase in FIV for the safety-related thermowells and probes. [[]] and no further evaluation of FIV influence on safety-related thermowells and probes is required. Also, []] For NMP2, there is no increase in flowin these systems for MELLLA+. Therefore, there is no increase in FIV for the safety-related thermowells and probes. [[]] and no further evaluation of FIVinfluence on safety-related thermowells and probes is required. 3.4.2 FIV Influence on Reactor Internals Er evaluates the effect of theMELLLA+ operating domain expansion on the following components: shroud, shroud head andsteam separator-dryer, core spray (CS) line, low pressure coolant injection (LPCI) coupling, CRGT, in-core guide tubes, fuel channel, LPRM / intermediate range monitor (IRM) tubes, jetpumps, jet pump sensing lines (JPSLs), and FW sparger. The MELLLA+ operating domainexpansion results in decreased core and recirculation flow as well as no increase in the MS and3-11 NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION -CLASS I (PUBLIC)FW flow rates. [[]] the effect of the MELLLA+operating domain expansion is presented for the following components: Component(s) MELLLA+ ResultsShroudShroud Head and SteamSeparator-Dryer CS LineLPCI CouplingCRGTIn-Core Guide TubesFuel ChannelLPRM/IRM TubesJet PumpsJPSLsFW SpargerFor NMP2, the MELLLA+ operating domain expansion results in decreased core andrecirculation flow as well as no increase in the MS and FW flow rates. The numerical valuesshowing a decrease in core and recirculation flow as well as no increase in maximum steam orFW flow rates are presented in Table 1-2. As presented in the table above, [[]] The reduced CF and recirculation flow3-12 NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION -CLASS I (PUBLIC)in the MELLLA+ domain [[]] Therefore, no further evaluation of the FIV influence on reactor internals isrequired for the NMP2 MELLLA+ operating domain expansion. Er3.5 PIPING EVALUATION 3.5.1 Reactor Coolant Pressure Boundary PipingThe RCPB piping systems evaluation consists of a number of safety-related piping subsystems that move fluid through the reactor and other safety systems. The topics addressed in thisevaluation are:Topic M+LTR Disposition NMP2 ResultMain Steam and Feedwater (Inside Containment) Recirculation and Control Rod DriveReactor Core Isolation Cooling (RCIC)High Pressure Core Spray (HPCS)RWCULow Pressure Core Spray (LPCS)Standby Liquid ControlResidual Heat Removal (RHR)RPV Head Vent LineSRV Discharge Line (SRVDL)Safety-Related Thermowells The piping systems are required to comply with the structural requirements and Pressure Vessel (BPV) Code (or an equivalent Code) applicable at theor the governing code used in the stress analysis for a modified component. of the ASME Boilertime of construction 3.5.1.1 Main Steam and Feedwater Piping Inside Containment Er]] the system temperatures, pressures, and flows in the MELLLA+operating domain are within the range of rated operating parameters for the MS and FW pipingsystem (inside containment). [[1]the temperatures, pressures, and flows in MS and FW systems for MELLLA+ operation are3-13 NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION -CLASS I (PUBLIC)within the range of rated operating parameters for those systems, no further evaluation isrequired related to RCPB piping for MS and FW piping inside containment. [[ ]] for NMP2, the MS and connected branch piping (i.e., RCIC steam lines) and FW temperatures, pressures, and flows are within therated operating parameters for the MS and FW systems. MS and FW temperatures, flows, andpressures at MELLLA+ conditions are bounded by the EPU temperatures, flows, and pressures, and as such are within the design values used in the design of the piping and supports chosen forworst case conditions. NMP2 MS and FW piping inside containment is designed in accordance with the original code of record, ASME BPV Code, Section III, Subsection NB, 1974 Edition.[[]] the temperatures, pressures, and flows in NMP2 MS and FWsystems for MELLLA+ operation are within the range of rated operating parameters for thosesystems, and no further evaluation is required related to the NMP2 RCPB piping for MS and FWinside containment. [I ]] as discussed in Section 3.3.3,the MCO may increase during the cycle when a plant is operating at or near the MELLLA+minimum CF rate. The generic disposition concludes that the change in erosion/corrosion ratesas a result of increased carryover is adequately managed by the existing programs discussed inSection 10.7.2.Er ]], the MCO for NMP2 may increase to a maximumof 0.25 wt.% during the cycle when NMP2 is operating at or near the MELLLA+ minimum CFrate. NMP2 implements programs adequate to manage this change in the erosion/corrosion rateas described in Section 10.7.2.The effect of MELLLA+ on the EPU AP load SC 09-01 evaluation has determined that theamplified response spectra (ARS) remains conservative for the rated power MELLLA+ Point N(Figure 1-1). The off-rated SC 09-01 methods show minor shifts in the ARS for selected nodes(power-flow map Points A and N in Figure 1-1) as compared to the EPU bounding spectrum. The review of the EPU SC 09-01 AP load assessments show the minor shifts represent aninsignificant change in the total load combination for these piping systems such that theconclusions reached for the EPU assessment remain unchanged. 3.5.1.2 Reactor Recirculation and Control Rod Drive Systems]] there is no change in the maximum operating systemtemperatures, pressures, and flows in the MELLLA+ operating domain for the recirculation piping system and attached RHR piping system. [[3-14 NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION -CLASS I (PUBLIC)]] no further evaluation of the RCPB piping -reactor recirculation and CRDsystems is required for MELLLA+ operating domain expansion. [[ ]] for NMP2, the reactorrecirculation and CRD system temperatures, flows, and pressures at MELLLA+ conditions arebounded by the EPU temperatures, flows, and pressures, and as such are within the design valuesused in the design of the piping and supports chosen for worst case conditions. 3.5.1.3 Other RCPB Piping Systems3.5.1.3.1 Other RCPB Piping Systems -HPCS, LPCS, RHR/LPCI, and SLS]] Because the piping systems meeting the criteria [[]] their susceptibility toerosion/corrosion does not increase, and no further evaluation of these other RCPB pipingsystems is required. [[ ]] MELLLA+ operating domainexpansion for NMP2 does not change the maximum operating temperature,

pressure, or flow rateof any of the following systems:

HPCS, LPCS, RHR/LPCI, and SLS.HPCS, LPCS, RHR/LPCI, and SLS temperatures, flows, and pressures at MELLLA+ conditions are bounded by the EPU temperatures, flows, and pressures, and as such are within the designvalues used in the design of the piping and supports chosen for worst case conditions. Each of these NMP2 systems [[]] their susceptibility toerosion/corrosion does not increase, and no further evaluation of these other RCPB pipingsystems is required for NMP2.3.5.1.3.2 Other RCPB Piping Systems -RPV Head Vent Line and SRV Discharge Lines[[3-15 NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION -CLASS I (PUBLIC)]] For the RPV head vent line and theSRVDL, there is no change in the temperature,

pressure, or flows in these systems as a result ofMELLLA+ operating domain expansion.

Because the piping systems have no change in systemtemperature, pressure or flow as a result of MELLLA+ operating domain expansion, [[]] Their susceptibility to erosion/corrosion does not increase, andno further evaluation of these other RCPB piping systems is required. [[ ]] MELLLA+ operating domainexpansion for NMP2 does not change the maximum operating temperature,

pressure, or flow rateof any of the following piping systems:

RPV head vent line and SRVDL.RPV head vent line and SRVDL temperatures, flows, and pressures at MELLLA+ conditions arebounded by the EPU temperatures, flows, and pressures, and as such are within the design valuesused in the design of the piping and supports chosen for worst case conditions. Additionally, there is no flow through the SRVDL during normal operating conditions. The RPV head vent line and the SRVDL are unaffected by MELLLA+ operating domainexpansion. [[ ]] their susceptibility to erosion/corrosion does not increase, and no further evaluation of these other RCPB piping systems is required forNMP2.3.5.1.3.3 Other RCPB Piping Systems -RWCU[[]] Because the RWCU system has no change insystem temperature, pressure or flow as a result of MELLLA+ operating domain expansion, [[]] RWCU system susceptibility to erosion/corrosion does notincrease, and no further evaluation of the RWCU system is required. Er ]] MELLLA+ operating domainexpansion for NMP2 does not change the maximum operating temperature,

pressure, or flow rateof the RWCU system. RWCU system temperatures, flows, and pressures at MELLLA+conditions are bounded by the EPU temperatures, flows, and pressures, and as such are withinthe design values used in the design of the piping and supports chosen for worst case conditions.

The NMP2 RWCU system is unaffected by MELLLA+ operating domain expansion. Er ]] the RWCU system susceptibility toerosion/corrosion does not increase, and no further evaluation of the RWCU system is required. 3.5.1.3.4 Other RCPB Piping Systems -Safety-Related Thermowells [[]] Because the RCPB pipingsystems evaluated for EPU do not experience any increase in pressure, temperature, or flow atMELLLA+, their susceptibility to erosion/corrosion does not increase, and no further evaluation of safety-related thermowells is required for NMP2.3-16 NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION -CLASS I (PUBLIC)]] the NMP2 safety-related thermowells are unaffected by MELLLA+ as the evaluations performed for the currently licensed operating domain are bounding for MELLLA+ conditions. [[Their susceptibility to erosion/corrosion does not increase and no further evaluation of safety-related thermowells is required for NMP2.Because all of the piping systems in Section 3.5.1.3 meet the criteria listed [[]] their susceptibility toerosion/corrosion does not increase, and no further evaluation of these other RCPB pipingsystems is required. 3.5.1.4 Other than Category "A" RCPB MaterialAs required by M+LTR SER Limitation and Condition 12.9, the following discussion ispresented regarding other than Category "A" materials that exist in the RCPB piping.Category "A" is assumed to mean intergranular stress corrosion cracking (IGSCC) Category "A"that is a resistant material to IGSCC for BWR piping weldments in accordance with GenericLetter (GL) 88-01 (Reference 18). Other than Category "A" is assumed to mean non-resistant orcracked materials for IGSCC BWR piping weldments in accordance with GL 88-01 (IGSCCCategories B through G). USAR Section 5.2-5 is only a general RCPB list and is not specifically related to IGSCC. The SER for GL 88-01, along with the associated technical evaluation, establishes the IGSCC categories and initial IGSCC related bases. The current IGSCC programis located within the in-service inspection (ISI) program plan (CNG-NMP2-ISI-003). CNG-NMP2-ISI-003, Section 6.1 specifically identifies 49 welds that are in the IGSCC otherthan Category "A" (Categories D and E shown in Tables 6-1 and 6-2 and summarized inTable 6-5 and Appendix E). CNG-NMP2-ISI-003-10 shows the implementation schedule andhas the "ASME Section XI Category Item No." column as either "GLD" or "GL-E," whichidentifies the location of the weld.The NMP2 ISI program for all ASME Code Class 1 and 2 RCPB piping is in accordance with anNRC staff approved alternate risk-informed inspection program utilizing the NRC approvedElectric Power Research Institute (EPRI) methodology, Technical Report TR-1 12657,Revision B-A (Reference 19). In addition to the ASME Code, Section XI and the alternate risk-informed

programs, NMP2 implements an augmented IGSCC inspection program in accordance with GL 88-01 (Reference 18), NUREG-0313 (Reference 20), and as modified by Boiling WaterReactor Vessel and Internals Project (BWRVIP)-75 (Reference

21) for IGSCC Category D weldexamination frequency using normal water chemistry.

NMP2 implements ASME Section XI,Appendix VIII for the performance demonstration for ultrasonic examination systemsadministrated through the EPRI performance demonstration initiative (PDI) program.Appendix VIII provided the requirements for the performance demonstration for ultrasonic examination procedures, equipment, and personnel to detect and size flaws. All of the above3-17 NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION -CLASS I (PUBLIC)programs have been credited as an aging management program during the NMP2 license renewalprocess.Continued implementation of the current program ensures the prompt identification of anydegradation of RCPB components experienced during MELLLA+ operating conditions. [[ ]] confirms that the augmented inspection programat NMP2 is adequate to address concerns related to other than Category "A" materials in theRCPB.3.5.2 Balance-of-Plant PipingThe BOP piping evaluation consists of a number of piping subsystems that move fluid throughsystems outside the RCPB. The topics considered in this section are:Topic M+LTR Disposition NMP2 ResultMain Steam and Feedwater (Outside Containment) Reactor Core Isolation CoolingHigh Pressure Core SprayLow Pressure Core SprayResidual Heat RemovalHigh Pressure Coolant Injection (HPCI)Offgas SystemContainment Air Monitoring Neutron Monitoring System3.5.2.1 Main Steam and Feedwater (Outside Containment) [[]] for all MS and FW piping systems, including the associated branch piping, thetemperature,

pressure, flow, and mechanical loads do not increase due to the MELLLA+operating domain expansion.

[[]] The susceptibility of these piping systemsto erosion/corrosion increases only for the MS piping; however, that erosion/corrosion will beadequately managed as discussed in Sections 3.5.1.1 and 10.7.2. [[no further evaluation is required for BOP Piping -MS and FW(outside containment). [ MELLLA+ operating domainexpansion for NMP2 does not change (no increase) the maximum operating temperature,

pressure, flow rate, or mechanical loads for the MS and FW piping outside containment.

MS andFW system temperatures, flows, and pressures at MELLLA+ conditions are bounded by the EPUtemperatures, flows, and pressures, and as such are within the design values used in the design of3-18 NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION -CLASS I (PUBLIC)the piping and supports chosen for worst case conditions. The NMP2 MS and FW piping outsidecontainment is unaffected by the MELLLA+ operating domain expansion. The NMP2 BOPpiping outside containment was typically designed in accordance with American NationalStandards Institute (ANSI) B331.1 (Reference

22) and as such, there were no fatigue analysesrequired or performed.

[[]], theFW piping outside containment susceptibility to erosion/corrosion does not increase, and nofurther evaluation is required. The MS outside containment susceptibility to erosion/corrosion does increase;

however, no further evaluation is required due to being adequately managed asdiscussed in Sections 3.5.1.1 and 10.7.2.i3.5.2.2 Other BOP Piping Systems3.5.2.2.1 Other BOP Piping Systems -RCIC, HPCS, LPCS, and RHR the loads and temperatures used in the analyses depend onthe containment hydrodynamic loads and temperature evaluation results (Section 4.1). [[]] The design basis LOCA dynamic loads including the pool swell loads, ventthrust loads, condensation oscillation (CO) loads, and chugging loads have been defined andevaluated for EPU. The pool temperatures due to a design basis LOCA were also defined forEPU. The values for the MELLLA+ operating domain remain within these bounding values.[[]] For these BOP piping systems,no further evaluation is required as a result of MELLLA+.The effect of MELLLA+ on the EPU AP load SC 09-01 evaluation has determined that the ARSremains conservative for the rated power MELLLA+ Point N (Figure 1-1). The off-rated SC 09-01 methods show minor shifts in the ARS for selected nodes (power-flow map Points Aand N in Figure 1-1) as compared to the EPU bounding spectrum.

The review of the EPUSC 09-01 AP load assessments show the minor shifts represent an insignificant change in thetotal load combination for these piping systems such that the conclusions reached for the EPUassessment remain unchanged. The MELLLA+ operating domain expansion for NMP2 does not change the maximum operating temperature,

pressure, or flow rate, or increase mechanical loads for any of the following systems:

RCIC, HPCS, LPCS, and RHR.RCIC, HPCS, LPCS, and RHR system temperatures, flows, and pressures at MELLLA+conditions are bounded by the EPU temperatures, flows, and pressures, and as such are withinthe design values used in the design of the piping and supports chosen for worst case conditions. ]] for each of the NMP2 systems described above, theloads and temperatures used in the analyses continue to be bounded by the loads and3-19 NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION -CLASS I (PUBLIC)temperatures used in the analyses performed for EPU. Section 4.1 shows that the NMP2 LOCAdynamic loads including the pool swell loads, vent thrust loads, CO loads, and chugging loadshave been evaluated and are bounded by the current design basis. The NMP2 peak suppression pool temperatures due to a design basis LOCA are also bounded by the current design basis.]] For these BOP pipingsystems, no further evaluation is required as a result of MELLLA+.3.5.2.2.2 Other BOP Piping Systems -Offgas System, Containment Air Monitoring, and Neutron Monitoring System]] For these BOP piping systems, no further evaluation is required as a result ofMELLLA+.[[ ]] there is no change to the NMP2reactor operating pressure or power level as a result of MELLLA+ operating domain expansion. The numerical values showing no increases in reactor operating pressure are presented inTable 1-2. [[]] For theseBOP piping systems, no further evaluation is required as a result of MELLLA+.Because all of the piping systems in Section 3.5.2.2 meet the criteria listed [[]] theirsusceptibility to erosion/corrosion does not increase, and no further evaluation of these otherBOP piping systems is required. I[[3.6 REACTOR RECIRCULATION SYSTEMThe topics addressed in this evaluation are:Topic M+LTR Disposition NMP2 ResultSystem Evaluation [[Net Positive Suction Head (NPSH)Single Loop Operation Flow Mismatch _ E3.6.1 System Evaluation [[ ]] all of theRRS operating conditions for the MELLLA+ operating domain are within the operating conditions in the current licensed operating domain. SLO is not allowed in the MELLLA+3-20 NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION -CLASS I (PUBLIC)operating domain. [[]] and no further evaluation of this topic is required. ]] the NMP2 RRS operating conditions in the MELLLA+ operating domain are within the operating conditions in the currentlicensed operating domain. For NMP2, there are no increases beyond design rated parameters inthe RRS temperature,

pressure, or flow rates as a result of MELLLA+ operating domainexpansion as compared to the current licensed operating domain. RRS system temperature forthe current licensed operating domain at 100% CF is 533.7°F and in the MELLLA+ operating domain at 85% CF is 530.7°F.

RRS system pressures, at the discharge of the recirculation pump,will increase from 1,314.5 psia for the current licensed operating domain to 1,340.5 psia in theMELLLA+ operating domain. This slight increase in pressure is due to the adjustment of theFCV to approximately the 59% opened position and is within the design operating pressure ofthe RRS system components. The numerical values showing no increases in RRS system flowrates are presented in Table 1-2. For NMP2, SLO is not allowed in the MELLLA+ operating domain. [[]] and no further evaluation ofthis topic is required. 3.6.2 Net Positive Suction Head]] Therefore, no further evaluation of the RRS NPSH topic is required. 3-21 NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION -CLASS I (PUBLIC)]] flow rate and FW temperature and, as described above, they are not changed by MELLLA+. [[]] The numerical values showing no significant changes in FW temperature and flow are presented in Table 1-2. Therefore, no furtherevaluation of the RRS NPSH topic is required. 3.6.3 Single Loop Operation [[ ]] SLO is notallowed in the MELLLA+ operating domain.[[ ]] SLO is not allowed in the MELLLA+ operating domain. NMP2 SLO operational limitations will be identified in TS 3.4.1. Therefore, SLO isnot allowed in the MELLLA+ operating range and is not affected by the MELLLA+ domainexpansion. 3.6.4 Flow MismatchFlow mismatch is discussed in Section 4.3.8.3.7 MAIN STEAM LINE FLOW RESTRICTORS The topics addressed in this evaluation are:Topic " M+LTR Disposition NMP2 ResultStructural Integrity ]] there is no increase in MS flow as a result of the MELLLA+ operating domainexpansion. [[]] and no further evaluation of this topic is required. ]] there is no increase in NMP2 MS flow as a resultof MELLLA+ operating domain expansion. The numerical values showing that MS flow doesnot increase as a result of MELLLA+ are presented in Table 1-2. [[]] and no further evaluation ofthis topic is required. 3-22 NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION -CLASS I (PUBLIC)3.8 MAIN STEAM ISOLATION VALVESThe topics addressed in this evaluation are:Topic M+LTR Disposition NMP2 ResultIsolation Performance Valve Pressure Drop ]]]] there is no increase inMS pressure, flow, or pressure drop as a result of the MELLLA+ operating domain expansion. [[ ]]and no further evaluation of this topic is required. [[ ]] there is no significant change in NMP2 MSpressure, flow, or pressure drop as a result of MELLLA+ operating domain expansion. The MSpressure for the current licensed operating domain and in the MELLLA+ operating domain is1,035 psia. The numerical values showing that MS flow does not increase as a result ofMELLLA+ are presented in Table 1-2. The total MSL pressure drop at the TSVs is notsignificantly changed for MELLLA+; the MSIV pressure drop is also not significantly changed.i and no further evaluation of this topic is required. 1]3.9 REACTOR CORE ISOLATION COOLINGThe RCIC system provides inventory makeup to the reactor vessel when the vessel is isolatedfrom the normal high pressure makeup systems. The topics addressed in this evaluation are:Topic M+LTR Disposition NMP2 ResultSystem Hardware [[System Initiation Net Positive Suction HeadInventory Makeup Level Margin to Top of Active Fuel (TAF) F3.9.1 System Hardwarethere are no changes to the RCIC system hardware as a result of MELLLA+ operating domainexpansion. [[ ]] there are no changes to the NMP2 RCIC systemhardware as a result of MELLLA+.3-23 NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION -CLASS I (PUBLIC)3.9.2 System Initiation [[ ]] thereare no changes to the normal reactor operating

pressure, decay heat, or SRV setpoints as a resultof MELLLA+ operating domain expansion.

[[no further evaluation of this topic is required. ]] there are no changes to the normal reactoroperating

pressure, decay heat, or SRV setpoints as a result of MELLLA+ operating domainexpansion.

The NMP2 reactor operating pressure for the current licensed operating domain andin the MELLLA+ operating domain remain unchanged. The numerical values showing thatreactor operating pressure does not increase as a result of MELLLA+ are presented in Table 1-2.As described in Section 1.2.3, the generic disposition in the M+LTR concludes that there is noincrease in decay heat as a result of MELLLA+ operating domain expansion. As discussed inSection 3.1.2, SRV setpoints are unchanged by MELLLA+ operating domain expansion. Therefore, for NMP2, [[]] No further evaluation of this topic is required. 3.9.3 Net Positive Suction Head[[ ]] the NPSHavailable for the RCIC pump [[]] For ATWS(Section 9.3) and fire protection (Section 6.7), operation of the RCIC system at suppression pooltemperatures greater than the operational limit may be accomplished by using the CST volume asthe source of water. Therefore, the specified operational temperature limit for the process waterdoes not change with MELLLA+. The NPSH required by the RCIC pump [[]] Therefore, no further evaluation is required for this topic.]] for NMP2, there are no physical changes to thepump suction configuration. The NMP2 RCIC flow rate for the current licensed operating domain and in the MELLLA+ operating domain is 600 gpm. Minimum atmospheric pressure in3-24 NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION -CLASS I (PUBLIC)the suppression chamber and the CST for the current licensed operating domain and in theMELLLA+ operating domain does not change. The RCIC system has the capability of using theCST or the suppression pool as a suction source at EPU and MELLLA+ conditions. For ATWS(Section 9.3) and fire protection (Section 6.7), operation of the RCIC system at suppression pooltemperatures greater than the operational limit may be accomplished by using the CST volume asthe source of the water. Therefore, the specified operational temperature limit for the processwater does not change with MELLLA+. In addition, the MELLLA+ suppression pooltemperature following an ATWS is bounded by EPU.The design basis function of the RCIC system is to provide coolant to the reactor vessel so thatthe core is not uncovered as a result of loss of off-site alternating current (AC) power or for aloss of feedwater (LOFW) event.The NPSH required by the NMP2 RCIC pump [[]] Therefore, no furtherevaluation is required for this topic.3.9.4 Inventory Makeup Level Margin to TAFThe makeup capacity of RCIC and the level margin to the TAF are evaluated in Section 9.1.3.3.10 RESIDUAL HEAT REMOVAL SYSTEMThe RHR system is designed to restore and maintain the reactor coolant inventory following aLOCA and remove reactor decay heat following reactor shutdown for normal, transient, andaccident conditions. The topics addressed in this evaluation are:Topic M+LTR Disposition NMP2 ResultLow Pressure Coolant Injection ModeSuppression Pool and Containment Spray Cooling ModesShutdown Cooling (SDC) ModeSteam Condensing ModeFuel Pool Cooling Assist ]]The primary design parameters for the RHR system are the decay heat in the core and theamount of reactor heat discharged into the containment during a LOCA. The RHR systemoperates in various modes, depending on plant conditions. [[]]3.10.1 Low Pressure Coolant Injection ModeThe LPCI mode, as it supports the LOCA response, is discussed in Section 4.2.4, Low PressureCoolant Injection. 3-25 NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION -CLASS I (PUBLIC)3.10.2 Suppression Pool and Containment Spray Cooling Modes]] the SPC mode is manually initiated to maintain thecontainment pressure and suppression pool temperature within design limits following isolation transients or a postulated LOCA. The short-term containment

response, for the first 30 secondsof the event, does not credit the containment spray in the analyses.

[[]] Therefore, no further evaluation is required for this topic.3.10.3 Shutdown Cooling Mode[]] theSDC mode is designed to remove the sensible and decay heat from the reactor primary systemduring a normal reactor shutdown. This non-safety related mode allows the reactor to be cooleddown within a certain time, so that the SDC mode of operation does not become a critical pathduring refueling operations. [[]] Therefore, no further evaluation is required for this topic.3.10.4 Steam Condensing ModeThe steam condensing mode is not applicable to NMP2.3.10.5 Fuel Pool Cooling Assist ModeThe fuel pool cooling assist mode, using existing RHR heat removal capacity, providessupplemental fuel pool cooling in the event that the fuel pool heat load exceeds the capability ofthe fuel pool cooling and cleanup system. [[]] Therefore, there is no effect on the fuel poolcooling assist mode.3.11 REACTOR WATER CLEANUP SYSTEMThe topics addressed in this evaluation are:Topic M+LTR Disposition NMP2 ResultSystem Performance [[Containment Isolation 3-26 NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION -CLASS I (PUBLIC)3.11.1 System Performance ER]] the MELLLA+ operating domain expansion does not change the pressure or fluidthermal conditions experienced by the RWCU system. Operation in the MELLLA+ operating domain does not increase the quantity of fission products, corrosion

products, and other solubleand insoluble impurities in the reactor water. Reactor water chemistry is within fuel warrantyand TS limits on effluent conductivity and particulate concentration, and thus, no changes will bemade in water quality requirements.

[[ ]] for NMP2, there is no totalincrease in the quantity of fission products, corrosion

products, and other soluble and insoluble radionuclide impurities in the reactor water (see Section 8.4). Consistent with the genericdisposition discussed above, for NMP2, there is no significant change in the FW linetemperature,

pressure, or flow rate. FW line temperature for the current licensed operating domain and in the MELLLA+ operating domain is 440.5'F (upstream of the RWCU return).

Asshown in Table 1-2, the FW flow rate in the MELLLA+ operating domain decreases slightlyfrom the flow rate in the current licensed operating domain. As discussed in Section 1.2, reactorpressure for the current licensed operating domain and in the MELLLA+ operating domain doesnot change. Therefore, FW system resistance and operating conditions do not change and thepressure at the RWCU/FW system interface does not change. As discussed in Sections 1.2 and3.6, reactor and recirculation system parameters are bounded by or unchanged from EPUconditions. Therefore, there is no effect on RWCU inlet conditions due to MELLLA+. Becausethere is no change to the pressure or fluid thermal conditions experienced by the RWCU system,and because there is no total increase in the quantity of fission products, corrosion

products, andother soluble and insoluble radionuclide impurities in the reactor water, [[]] Therefore, no further evaluation of this topic is required.

3.11.2 Containment Isolation ]] the RWCU system is a normally operating system with no safety-related functions otherthan containment isolation. [[]] because there is no change in the FW line pressure, temperature, and flow rate.[[ ]] for NMP2, there is no significant change in the FW line temperature,

pressure, or flow rate. The FW line temperature for thecurrent licensed operating domain and in the MELLLA+ operating domain is 440.5'F (upstream of the RWCU return).

As shown in Table 1-2, the maximum FW flow rate in the MELLLA+operating domain decreases slightly from the maximum flow rate in the current licensedoperating domain. As such, the FW flow rates in the MELLLA+ operating domain remain3-27 NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION -CLASS I (PUBLIC)within the FW flow rates in the current licensed operating domain. As discussed in Section 1.2,reactor pressure for the current licensed operating domain and in the MELLLA+ operating domain does not change. Therefore, FW system resistance and operating conditions do notchange and the pressure at the RWCU/FW system interface does not change for RWCU returnlines. As discussed in Section 3.11.1 above, there is no change to RWCU inlet conditions. 3-28 NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION -CLASS I (PUBLIC)Table 3-1 Key Results at 120% OLTPItem Parameter CLTP to M+120% OLTP Comparison I Azimuthal flux distribution at RPV ID Ratio of M+/CLTP peak flux is 0.982 Relative axial flux distribution at RPV ID No significant change3 Azimuthal flux distribution at shroud ID Ratio of M+/CLTP peak flux is 1.014 Relative axial flux distribution at shroud ID No significant change5 54-EFPY axial fluence distribution at RPV ID Ratio of M+/CLTP peak fluence is 0.996 54-EFPY axial fluence at shroud H4 weld Ratio of M+/CLTP peak fluence is 1.027 Capsule (30 azimuth) flux Ratio of M+/CLTP flux is 1.028 Capsule lead factor Ratio of M+/CLTP lead factor is 1.059 Peak flux at top guide Ratio of M+/CLTP peak flux is 1.0710 Peak flux at core plate Ratio of M+/CLTP peak flux is 0.9411 54-EFPY peak fluence at top guide Ratio of M+/CLTP peak fluence is 1.0612 54-EFPY peak fluence at core plate Ratio of M+/CLTP peak fluence is 0.943-29 NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION -CLASS I (PUBLIC)4.0 ENGINEERED SAFETY FEATURESThis section addresses the evaluations that are applicable to MELLLA+.4.1 CONTAINMENT SYSTEM PERFORMANCE The topics addressed in this evaluation are:Topic M+LTR Disposition NMP2 ResultShort-Term Pressure and Temperature ResponseLong-Term Suppression Pool Temperature ResponseContainment Dynamic LoadsLoss-of-Coolant Accident LoadsSubcompartment Pressurization Safety Relief Valve LoadsSafety Relief Valve Containment Dynamic LoadsSafety-Relief Valve Piping LoadsContainment Isolation Generic Letter 89-10Generic Letter 95-07Generic Letter 96-064.1.1 Short-Term Pressure and Temperature ResponseAccording to Section 4.1.1 of the M+LTR (Reference 1), operation in the MELLLA+ range maychange the break energy for the DBA recirculation suction line break (RSLB). The break energyis derived from the break flow rate and enthalpy. [[]] NMP2 short-term RSLB containment temperature and pressure responses are affected by the change in enthalpy as a result of MELLLA+ operating domain expansion. The short-term RSLB analyses cases at MELLLA+ demonstrate that peak DW temperatures from the short-term RSLB for the current licensed operating domain and the MELLLA+operating domain are bounded by the CLTP results reported in Reference 23 which remainbelow the design limit of 340'F.For NMP2, there are two peak pressures; the first peak occurring -25 seconds (end of initialvessel inventory blowdown) and the second peak occurring -150 seconds (end of blowdownphase). The first peak is typically determined by standard short-term

analysis, while the secondpeak is determined by the extended short-term analysis.

The first peak is lower than the secondpeak; the difference is -0.5 psi for EPU. The extended short-term analysis is not sensitive to thesubtle initial changes in vessel mass and energy associated with operation at various points in theoperating domain. Due to the extended time frame until the DW reaches the second peakpressure conditions, it is recognized that the minor variability in the initial vessel inventory energy associated with various points in the operating range would have negligible effect in4-1 NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION -CLASS I (PUBLIC)comparison to the overall mass and energy contributions to the DW at the time of the secondpeak. Therefore, the effect of MELLLA+ is assessed from the results of the standard short-term analysis using more detailed LAMB break flow model, which captures the subcooling effectwhen operating in MELLLA+ operating domain. Several short-term cases are analyzed forMELLLA+ statepoints and results compared to EPU short-term results. The results show thatEPU short-term peak pressure bounds the MELLLA+ peak pressures. The peak DW-to-wetwell differential pressures for operation in the MELLLA+ operating domain are bounded by thosepreviously reported in Reference 23 for the current CLTP operation. [[]]4.1.1.1 Long-Term Suppression Pool Cooling Temperature ResponseTherefore, no further evaluation of this topic is required. [[ ]] the sensible and decay heat do notincrease as a result of MELLLA+ operating domain expansion. [[]] No further evaluation of thistopic is required. 4.1.2 Containment Dynamic Loads4.1.2.1 Loss-of-Coolant Accident LoadsAs described in the M+LTR, a [[ ]] evaluation is performed to determine theeffect of MELLLA+ on the LOCA containment dynamic loads. Results from [[]] are used to evaluate the effect of the MELLLA+ operating domain expansion onLOCA containment dynamic loads. The LOCA dynamic loads include vent clearing jet loads,pool swell, CO, and chugging. 4-2 NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION -CLASS I (PUBLIC)These loads have been defined generically for Mark II plants as part of the Mark II containment program and are described in detail in the Mark II Containment Dynamic Forcing Functions Report (DFFR) (Reference 24). The DFFR was reviewed and approved by the NRC inNUREG-0808 and NUREG-0487 (References 9 and 25). The specific application of these loadsto NMP2 is described in Section 6A.4 of the NMP2 USAR (Reference 26).The results of the [[ ]] LOCA containment dynamic loads evaluation demonstrate that existing vent clearing jet loads, pool swell, CO, and chugging load definitions remainbounding for operation in the MELLLA+ operating domain. Therefore, the LOCA containment dynamic loads are not affected by the MELLLA+ operating domain expansion. 4.1.2.2 Subcompartment Pressurization Reduced FW temperature increases the subcooling in the FW and reactor recirculation lines,which increases the break flow rates for liquid line breaks. The current subcompartment pressurization loads evaluations consider the current licensed operating domain, which includesan operational band of-20'F (with a minimum FW temperature of 420.5°F at rated power). Thisanalysis concludes that break flow rates for liquid line breaks such as FW and recirculation linebreaks for the MELLLA+ expanded operating domain are bounded by the break flow rates forthe current licensed operating domain. This operation band remains valid for the MELLLA+operating domain.4.1.2.2.1 Annulus Pressurization Load Evaluation The results from the updated dynamic analyses, including effects from both EPU and the non-conservative assumptions, were compared against those used as input to the component structural analyses of record. The effect of the increase in AP loads on the total component stresses is reduced when the AP loads are combined with the SSE seismic loads by the squareroot of the sum of the squares in the faulted load combination. The SSE seismic loads in the loadcombination are not affected by EPU. The effect of MELLLA+ on the EPU AP load SC 09-01evaluation has determined that the ARS remains conservative for the rated power MELLLA+.The off-rated SC 09-01 methods show minor changes in the sub compartment pressurization related to the updated methods associated with SC 09-01 when combined with the jet reactionloads and jet impingement loads using conservative assumptions. The minor changes in ARSfrequency when combined in the faulted load combination with seismic show that theconclusions reached for the EPU assessment remain bounding with a few locations showingminor increases. The results of these evaluations show that all reactor vessel and internals, andassociated vessel attachments and supports remain within design basis faulted allowable limits.Because the MELLLA+ operating domain AP subcompartment pressurization are bound by thecurrent licensed operating domain, no further evaluation of this topic is required. The evaluation of the NMP2-specific AP subcompartment pressurization is determined to beacceptable for NMP2.4-3 NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION -CLASS I (PUBLIC)4.1.2.2.2 Drywell Head Subcompartment Pressurization Evaluation The pressure loading on the DW head refueling bulkhead plate to a postulated break in the RCIChead spray line in the DW head subcompartment is not affected by MELLLA+. The pressureand temperature/enthalpy for the RCIC is either not affected or may be slightly reduced in valuecompared to EPU. The postulated RSLB in the DW affects the upward pressure loading on thebulkhead plate and remains bounded by the EPU evaluation as the fluid enthalpy at the breaklocation is not significantly affected (less than 1%), while the break location pressure is the sameas at CLTP. Therefore, the DW head refueling bulkhead plate design margins is unchanged. Because the MELLLA+ operating domain DW head subcompartment pressurization is bound bythe current licensed operating domain, no further evaluation of this topic is required. The evaluation of the NMP2-specific DW head subcompartment pressurization is determined tobe acceptable for NMP2.4.1.2.2.3 Biological Shield Wall Subcompartment Pressurization Evaluation The differential pressure loading on the biological shield wall (BSW) is not significantly affectedby MELLLA+. The pressure and temperature/enthalpy for the high energy systems penetrating the BSW (recirculation, LPCS, HPCS, feedwater) are either not affected or may be slightlyreduced in value compared to EPU. The peak BSW differential pressure load resulting from thelimiting recirculation pump discharge line break at CLTP and MELLLA+ conditions remainsbounded by the EPU evaluations and remains below the BSW design differential pressure. Inaddition, the EPU AP load SC 09-01 evaluation for the BSW remains conservative whenconsidering MELLLA+ and the off-rated operating conditions. Because the MELLLA+ operating domain BSW subcompartment pressurization is bound by thecurrent licensed operating domain, no further evaluation of this topic is required. The evaluation of the NMP2-specific BSW subcompartment pressurization is determined to beacceptable for NMP2.4.1.2.3 SRV Piping -Containment Dynamic Loadsbecause the sensible and decay heat do not change in the MELLLA+ operating domain, andbecause the SRV setpoints do not change, the SRV loads do not change. Therefore, no furtherevaluation of this topic is required. [[ ]] the sensible and decay heat do notchange as a result of MELLLA+ operating domain expansion. This response is discussed inSection 1.2.3. Also, there is no change to the NMP2 SRV setpoints as a result of MELLLA+operating domain expansion. This topic is discussed in Section 3.1.2. Therefore, there is nochange to the NMP2 SRV loads. No further evaluation of this topic is required. 4-4 NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION -CLASS I (PUBLIC)4.1.2.4 SRV -Containment Dynamic LoadsThe basis for the M+LTR (Reference

1) generic SRV containment load disposition wasconfirmed to be applicable to NMP2.Section 4.1 of the M+LTR (Reference

1) provides the following generic disposition for the effectof MELLLA+ on long-term suppression pool temperature response and SRV loads;4.1.3 Containment Isolation

]] evaluation is required todemonstrate the adequacy of the containment isolation system.]] Therefore, no containment isolation system evaluations are required forNMP2.[[4.1.4 Generic Letter 89-10Topic M+LTR Disposition NMP2 ResultGeneric Letter 89-10 Generic Letter 89-16Generic Letter 95-07Generic Letter 96-06 ]] evaluation toevaluate changes to the GL 89-10 program is required. 4-5 NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION -CLASS I (PUBLIC)]] Sections 6.6 and 10.1 confirm that other parameters with the potential toaffect the capability of safety-related MOVs, such as the ambient temperature

profile, arebounded by the current design basis. Therefore, a separate plant-specific GL 89-10 MOVprogram evaluation is not required.

4.1.5 Generic Letter 89-16GL 89-16 (Reference

28) is not applicable to NMP2.4.1.6 Generic Letter 95-07evaluation of the GL 95-07 program is required.

]] Therefore, no GL 95-07 evaluation is required. 4.1.7 Generic Letter 96-06[[Ievaluation of the GL 96-06 program is required. [[]] Therefore, no GL 96-06 evaluation is required. O[[4.2 EMERGENCY CORE COOLING SYSTEMSThe ECCS includes HPCS, the LPCS system, the LPCI mode of the RHR system, and the ADS.The topics addressed in this evaluation are:4-6 NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION -CLASS I (PUBLIC)Topic M+LTR Disposition NMP2 ResultHigh Pressure Coolant Injection N/A to NMP2 N/A to NMP2High Pressure Core SprayLow Pressure Core SprayLow Pressure Coolant Injection Mode of the Residual HeatRemoval SystemAutomatic Depressurization SystemEmergency Core Cooling System Net Positive Suction Head4.2.1 High Pressure Coolant Injection The HPCI system is not applicable to NMP2.4.2.2 High Pressure Core Spray[[ ]] the HPCSsystem is designed to spray water into the reactor vessel over a wide range of operating pressures. In the event of a small break LOCA that does not immediately depressurize thereactor vessel, the HPCS system provides reactor vessel coolant inventory makeup to maintainreactor water level and help depressurize the reactor vessel. This system also provides spraycooling for long-term core cooling after a LOCA. In addition, the HPCS system serves as abackup to the RCIC system to provide makeup water in the event of a LOFW flow transient. Forthe MELLLA+ operating domain expansion, there is no change in the normal reactor operating

pressure, decay heat, and the SRV setpoints.

[[no further evaluation of the HPCSsystem is required. [[ ]] there is no change to the normal reactor pressure asa result of MELLLA+ operating domain expansion. The numerical values showing no increases in reactor operating pressure are presented in Table 1-2. The sensible and decay heat do notchange as a result of MELLLA+ operating domain expansion. This response is discussed inSection 1.2.3. Also, there is no change to the NMP2 SRV setpoints as a result of MELLLA+operating domain expansion. This topic is discussed in Section 3.1.2. [[]] and no further evaluation of the HPCS system is required. 4-7 NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION -CLASS I (PUBLIC)4.2.3 Low Pressure Core Spray[I ]] the LPCS systemis automatically initiated in the event of a LOCA. The primary purpose of the LPCS system is toprovide reactor coolant makeup for a large break LOCA and for any small break LOCA after thereactor vessel has depressurized. It also provides spray cooling for long-term core cooling in theevent of a LOCA. [[]] no further evaluation of the LPCS system for MELLLA+.]] there is no change to the reactor pressure as a resultof MELLLA+ operating domain expansion. The numerical values showing no increases inreactor operating pressure are presented in Table 1-2. [[]] and no further evaluation of the LPCS system is required. [[4.2.4 Low Pressure Coolant Injection [[ ]] the LPCI mode of the RHRsystem is automatically initiated in the event of a LOCA. The primary purpose of the LPCImode is to provide reactor coolant makeup for a large break LOCA and for any small breakLOCA after the reactor vessel has depressurized. [[]] no further evaluation ofLPCI for MELLLA+.[[ ]] there is no change to the reactor pressure as a resultof MELLLA+ operating domain expansion. The numerical values showing no increases inreactor operating pressure are presented in Table 1-2. [[]) and no further evaluation of the LPCI mode is required. In the event of a design basis4-8 NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION -CLASS I (PUBLIC)Appendix R event discussed in Section 6.7, the LPCI mode of RHR injects water into the reactorvessel to restore inventory and maintain core cooling following vessel depressurization. 4.2.5 Automatic Depressurization SystemR the ADS uses SRVs toreduce the reactor pressure following a small break LOCA, when it is assumed that the highpressure systems have failed. This allows the LPCS and LPCI systems to inject coolant into thereactor vessel. [[]] no further evaluation of the ADS isrequired. [[]] and no further evaluation of the ADS is required. Er4.2.6 ECCS Net Positive Suction HeadEr ]] theMELLLA+ operating domain expansion does not result in an increase in the heat addition to thesuppression pool following a LOCA, station blackout (SBO), or Appendix R event. [[]] There are nophysical changes in the piping or system arrangement. There is no change in the operator actionsto throttle the RHR and CS pumps.Er ]] there is no increase in the heat addition to thesuppression pool following a LOCA, SBO, or Appendix R event (see Sections 4.1.2, 9.3.2, and6.7, respectively). For NMP2, the most limiting case for ECCS NPSH is confirmed to occur atthe long-term suppression pool temperature during a LOCA, [[]] There are also no changes in NMP2 ECCS pipingor system arrangement. There is no change in the operator actions to throttle the RHR and CSpumps. Therefore, all criteria related E[ ]] of ECCS-NPSH are met,and no further evaluation is required. The suppression pool temperature following an ATWS is bounded by EPU.4-9 NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION -CLASS I (PUBLIC)M+LTR SER Limitation and Condition 12.23.9 requires that plant-specific applications mustreview the safety system specifications to ensure that all of the assumptions used for the ATWSSE indeed apply to their plant-specific conditions including providing information on crucialsystems like HPCI and physical limitations like NPSH and maximum vessel pressure that RCICand HPCI can inject. NMP2 does not have a HPCI system. In response to an NRC RAI for theEPU LAR, NMP2 performed NPSH evaluation for ECCS pumps for variety of scenarios including DBA-LOCA and ATWS. The NPSH evaluation did not credit containment accidentoverpressure (Reference 31). As discussed above, MELLLA+ suppression pool temperature forDBA-LOCA is bounded by EPU. In addition, MELLLA+ ATWS suppression pool temperature is also bounded by EPU ATWS as shown in Table 9-4. Therefore, reduction in MELLLA+containment pressure has no effect on the ECCS pump operability in regard to NPSH.Therefore, NMP2 complies with M+LTR SER Limitation and Condition 12.23.9 related toNPSH and ECCS pump operability. The EPU analysis of ECCS NPSH remains bounding for MELLLA+. The NRC reviewed theECCS NPSH requirements as part of the EPU LAR, and stated in the NRC's SER for the NMP2EPU LAR dated December 22, 2011 (Reference

14) that the NMP2 ECCS NPSH meets theguidance in RG 1.1 (Reference 32), does not credit containment accident pressure to ensureadequate NPSH, and meets NRC staff guidance on NPSH uncertainty and operation in maximumerosion zone.4.3 EMERGENCY CORE COOLING SYSTEM PERFORMANCE The NMP2 ECCS is designed to provide protection against postulated LOCAs caused byruptures in the primary system piping. The ECCS performance characteristics do not change forthe MELLLA+ operating domain expansion.

The topics addressed in this evaluation are:Topic M+LTR Disposition NMP2 ResultLarge Break Peak Clad Temperature Small Break Peak Clad Temperature Local Cladding Oxidation Core-Wide Metal Water ReactionCoolable GeometryLong-Term CoolingFlow Mismatch LimitsThese topics are described in Sections 4.3.2 through 4.3.8.4.3.1 Break Spectrum Response and Limiting Single Failure]] The break spectrum response is determined by the ECCS network design and iscommon to all BWRs. SAFER evaluation experience shows that the basic break spectrum4-10 NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION -CLASS I (PUBLIC)response is not affected by changes in CF (Reference 33). [[M+LTR SER Limitation and Condition 12.14 requires that for plants that will implement MELLLA+, a sufficient number of small break sizes shall be analyzed at the rated EPU powerlevel to ensure that the peak peak cladding temperature (PCT) break size is identified. [[]]The factors influencing the selection of the limiting single failure for NMP2 are [[]] The trends discussed in the M+LTR regarding the first and second clad temperature peaks of large breaks are applicable to NMP2. [[]]The factors influencing the selection of the small break limiting single failure for NMP2 are4.3.2 Large Break Peak Clad Temperature The effect of MELLLA+ operating domain expansion on the NMP2 LOCA performance issimilar to that observed in the current licensed operating domain, which includes the MELLLAoperating domain low CF region. The PCT response following a large recirculation line breakhas two peaks. The first peak is determined by the boiling transition during CF coastdown earlyin the event. The second peak is determined by the core uncovery and reflooding. MELLLA+ operating domain expansion has two effects on the boiling transition and first peakPCT. First, the reduced CF causes the boiling transition to occur earlier and lower in the bundle.Second, the reduced CF causes the initial subcooling in the downcomer to be higher so that thebreak flow is greater in the early phase of the LOCA event. For a given power level, the earlyboiling transition times (boiling transitions that occur before jet pump uncovery) for NMP2occur earlier in the event and penetrate lower in the fuel bundle as the CF is reduced, but theeffect of the early boiling transition on the LOCA PCT depends on the particular conditions. Effect of MELLLA+ at Rated PowerThe PCT results are shown in the table at the end of this section. [[4-11 NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION -CLASS I (PUBLIC)Effect of MELLLA+ at Less Than Rated PowerM+LTR SER Limitation and Condition

12. 1O.a requires the M+SAR to provide a discussion onthe power/flow combination scoping calculations that were performed to identify the limitingstatepoints in terms of DBA-LOCA PCT response for the operation within the MELLLA+boundary.

As required by this limitation, [[]] The PCT results summarized below show that there are no unusualtrends in PCT in the MELLLA+ region and that there is margin to the 2,200'F PCT limit.Effect of Axial Power ShaveAs required by M+LTR SER Limitation and Condition 12.11 (Reference

1) and Methods LTRSER Limitation and Condition 9.7 (Reference

3) for MELLLA+ applications, the small and largebreak ECCS-LOCA analyses shall include top-peaked and mid-peaked power shape inestablishing the MAPLHGR and determining the PCT. This limitation is applicable to both thelicensing basis PCT and the upper bound PCT. The plant-specific applications should report thelimiting small and large break licensing basis and upper bound PCTs. [[4-12 NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION

-CLASS I (PUBLIC)Power/Flow' Nominal PCT (OF) 2 Appendix K PCT (OF) 21st Peak 2nd Peak 1st Peak 2nd PeakNotes: 1 Power level shown is percent at EPU condition. Flow level shown is percent of RCF.2 Results are for GE14 DBA large break.4.3.3 Small Break Peak Clad Temperature I[[Effect of MELLLA+ at Rated PowerThe PCT results are shown in the table at the end of this section. 1M+LTR SER Limitation and Condition 12.13 requires that the MELLLA+ plant-specific SARinclude calculations for the limiting small break at rated power/RCF and rated power/MELLLA+

boundary, if the small break PCT at rated power/RCF is within [[ ]] of the limitingAppendix K PCT. For NMP2, the small break PCT is limiting.

Therefore, small break PCTcalculations are performed for MELLLA+ flow, and the PCT results are shown in the table at theend of this section.Effect of MELLLA+ at Less Than Rated PowerM+LTR SER Limitation and Condition 12.1O.b requires that the M+SAR provide a justification as to why the transition statepoint ECCS-LOCA response bounds the 55% CF statepoint. ]] The PCT results4-13 NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION -CLASS I (PUBLIC)summarized below show that there are no unusual trends in PCT in the MELLLA+ region andthat there is margin to the 2,200'F PCT limit.Effect of Axial Power ShapeAs required by M+LTR SER Limitation and Condition 12.11 and Methods LTR SER Limitation and Condition 9.7 for MELLLA+ applications, the small and large break ECCS-LOCA analyseshave included top-peaked and mid-peaked power shapes in establishing the MAPLHGR anddetermining the PCT. This limitation is applicable to both the licensing basis PCT and the upperbound PCT. The plant-specific applications have confirmed that the limiting small and largebreak with [[]]Small Break Licensing Basis PCTReference 34 provides justification for the elimination of the 1,600'F upper bound PCT limit andgeneric justification that the licensing basis PCT will be conservative with respect to the upperbound PCT. The NRC SER in Reference 34 accepted this position by noting that, because plant-specific upper bound PCT calculations have been performed for all plants, other means may beused to demonstrate compliance with the original SER limitations. These other means areacceptable provided there are no significant changes to a plant's configuration that wouldinvalidate the existing upper bound PCT calculations. The changes in magnitude of the PCT dueto MELLLA+ demonstrate that this plant configuration change does not invalidate the existingupper bound PCT calculations. M+LTR SER Limitations and Conditions 12.12.a and 12.12.b and Methods LTR SER Limitation and Condition 9.8 also require that the ECCS-LOCA evaluation be performed for all statepoints in the upper boundary of the expanded operating domains. [[]] The calculated GEl4 licensing basis PCT is 1,580'F, based on the limiting casescenario. [[4-14 NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION -CLASS I (PUBLIC)Power/Flow' Nominal PCT (*F)2 Appendix K PCT (OF)2Notes:Power level shown is percent at EPU power level. Flow level shown is percent of RCF.2 Results are for GEl4 limiting small break.4.3.4 Local Cladding Oxidation Er]] Sections 4.3.2 and 4.3.3 that determine the effect on the PCT. [[]] and no further evaluation of this topic is required. Er ]] for NMP2, Sections 4.3.2 and4.3.3 show acceptable PCT results that meet the 2,200'F limit. [[]] and no furtherevaluation of this topic is required. 4.3.5 Core-Wide Metal Water Reaction Sections 4.3.2 and 4.3.3 that determine the effect on the PCT. [[]] and no further evaluation of this topic is required. ]] for NMP2, Sections 4.3.2 and4.3.3 show acceptable PCT results that meet the 2,200'F limit. [[]] and no furtherevaluation of this topic is required. 4-15 NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION -CLASS I (PUBLIC)4.3.6 Coolable Geometry]] NMP2's compliance with thecoolable geometry acceptance criteria was generically demonstrated as a GEH BWR 4.3.7 Long-Term Cooling NMP2's compliance with the long-term cooling acceptance criteria was generically demonstrated as a GEH BWR [[4.3.8 Flow Mismatch Limitslimits have been placed on recirculation drive flow mismatch over a range of CFs. For mostplants, the limits on flow mismatch are more relaxed at lower CF rates. The drive flowmismatch affects the CF coastdown following the break. The effect of the drive flow mismatchon the LOCA evaluation is similar to a small change in the initial CF. [[]] the discussion and trends in theM+LTR are applicable to NMP2. [[4-16 NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION -CLASS I (PUBLIC)]]4.4 MAIN CONTROL ROOM ATMOSPHERE CONTROL SYSTEMThe topics addressed in this evaluation are:Topic M+LTR Disposition NMP2 ResultIodine Intake[[ ]] theMELLLA+ operating domain expansion does not result in a change in the source terms or therelease rates (Section 8.0). [[]] Provided this criterion ismet, no further evaluation of the Main Control Room (MCR) atmosphere control system isrequired. [[ ]] there is no change in the NMP2source term or release rates as a result of MELLLA+ operating domain expansion. This topic isdiscussed in Section 8.0. [[]] No further evaluation ofthe MCR atmosphere control system is required. I[[4.5 STANDBY GAS TREATMENT SYSTEMThe topics addressed in this evaluation are:Topic M+LTR Disposition NMP2 ResultFlow CapacityIodine Removal Capability 4.5.1 Flow Capacity[ ]]theSGTS is designed to maintain secondary containment at a negative pressure and to filter theexhaust air for removal of fission products potentially present during abnormal conditions. Bylimiting the release of airborne particulates and halogens, the SGTS limits off-site dose following a postulated DBA. [[]] and no furtherevaluation of the SGTS flow is required. [[ ]] the design flow capacity of theNMP2 SGTS was selected to maintain the secondary containment at the required negativepressure to minimize the potential for exfiltration of air from the Reactor Building. [[4-17 NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION -CLASS I (PUBLIC)]] and no further evaluation is required. 4.5.2 Iodine Removal Capability [[]] the SGTS is designed to maintain secondary containment at a negative pressure and tofilter the exhaust air for removal of fission products potentially present during abnormalconditions. By limiting the release of airborne particulates and halogens, the SGTS limits off-site dose following a postulated DBA. [[]] the core fission product inventory isnot changed by the MELLLA+ operating domain expansion (Section 8.3), and coolant activitylevels are defined by TS and do not change, so no change occurs in the SGTS adsorber iodineloading, decay heat rates, or iodine removal efficiency. [[]] No further evaluation of this topic is required. 4.6 MAIN STEAM ISOLATION VALVE LEAKAGE CONTROL SYSTEMNMP2 does not use a MSIV leakage control system (LCS).4.7 POST-LOCA COMBUSTIBLE GAS CONTROL SYSTEMThe topics addressed in this evaluation are:M+LTRTopic NMP2 ResultPost-LOCA Combustible Gas Control ]]10 CFR 50.44 was revised in September 2003 and no longer defines a design basis LOCAhydrogen release. This new revision eliminates the requirements for hydrogen control systems tomitigate such a release. NMP2 has adopted the revised ruling per NMP2 license amendment Number 124, issued in April 2008, which relaxed the requirements for hydrogen and oxygenmonitoring. This amendment also eliminated the requirements for hydrogen recombiners for thepurpose of mitigating post-LOCA hydrogen

release, although NMP2 has chosen to leave therecombiners in place and remain functional.

NMPNS made commitments to maintain thehydrogen and oxygen monitoring systems capable of diagnosing beyond DBAs. MELLLA+operating domain expansion has no effect on the design of these systems or on the ability ofthese systems to perform their intended functions.

However, as this system is no longer required4-18 NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION

-CLASS I (PUBLIC)to be maintained as a post-LOCA combustible gas control system, no further evaluation isnecessary relative to the MELLLA+ operating domain expansion. The generic disposition of thesystem (under the M+LTR) is no longer applicable. [[4-19 NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION -CLASS I (PUBLIC)5.0 INSTRUMENTATION AND CONTROLThis section addresses the evaluations that are applicable to MELLLA+.5.1 NSSS MONITORING AND CONTROLChanges in process parameters resulting from the MELLLA+ operating domain expansion andtheir effects on instrument performance are evaluated in the following sections. The effect of theMELLLA+ operating domain expansion on the TS is addressed in Section 11.1 and the effect onthe allowable values (AVs) in Section 5.3. The topics addressed in this evaluation are:Topic M+LTR Disposition NMP2 ResultAverage Power Range, Intermediate Range,and Source Range MonitorsLocal Power Range MonitorsRod Block MonitorRod Worth Minimizer Traversing Incore Probes5.1.1 Average Power Range, Intermediate Range, and Source Range MonitorsI[[]] the APRM output signals are calibrated to read 100% at the CLTP.]] Using normal plant surveillance procedures, the IRMs may be adjusted to ensure adequate overlap with the SRMs and APRMs.Therefore, no further evaluation of the APRMs, IRMs, or SRMs is required for MELLLA+.[[ ]] there is no change in NMP2 corepower as a result of MELLLA+ operating domain expansion. [[]] TheAPRMs, IRMs, and SRMs are installed at NMP2 in accordance with the requirements established by the GEH design specifications. NMP2 uses normal plant procedures to adjust theIRMs to ensure adequate overlap with the SRMs and APRMs. Therefore, no further evaluation is required. 5.1.2 Local Power Range Monitors[[ ]] there is nochange in the neutron flux experienced by the LPRMs resulting from the MELLLA+ operating domain expansion. [[5-1 NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION -CLASS I (PUBLIC)]] No further evaluation of these topics is requiredfor MELLLA+.[[ ]] there is no change in the neutronflux experienced by the NMP2 LPRMs resulting from the MELLLA+ operating domainexpansion. Analysis was performed to confirm that bypass voiding at the D Level LPRM doesnot exceed 5%. Therefore, [[]] The LPRMs are installed at NMP2 in accordance with therequirements established by the GEH design specifications. No further evaluation of these topicsis required for MELLLA+.1]]5.1.3 Rod Block MonitorsEr ]] the RBM usesLPRM instrumentation inputs that are combined and referenced to an APRM channel. [[]] and as described in Sections 5.1.1and 5.1.2, the [[]] No further evaluation ofthese topics is required for MELLLA+.Section 9.1.1 evaluates the adequacy of the generic RBM setpoints. Er5.1.4 Rod Worth Minimizer ]] the function of the RWM is to support the operator by enforcing rod patterns untilreactor power has reached appropriate levels. The RWM functions to limit the local power in thecore to control the effects of the postulated control rod drop accident (CRDA) at low power.E[ r]Therefore, no further evaluation is required. [[ ]] the NMP2 RWM supports theoperator by enforcing rod patterns until reactor power has reached appropriate levels.E[ r]Therefore, no further evaluation is required. E[5-2 NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION -CLASS I (PUBLIC)5.1.5 Traversing Incore ProbesTo address the M+LTR SER Limitation and Condition 12.15, bypass voiding above the D-Level,an analysis was performed to identify the region on the MELLLA+ power/flow map that haspotentially unacceptable bypass voiding for the thermal traversing incore probes (TIPs) installed at NMP2. In the absence of bypass voiding greater than 5% no actions are required regarding theTIPs resulting from the MELLLA+ operating domain expansion. [[Analysis shows that there is a small region of the MELLLA+ power flow domain near point Min Figure 5-1 where the hot channel voiding at the TIP exit exceeds 5% thus requiring specificattention per Limitation and Condition 12.15. [[]] TIP operation and LPRM calibration in the remainder of the MELLLA+domain are not adversely affected by the void conditions in the bypass region. NMPNS controlroom operators and Reactor Engineers will be trained on this requirement and station procedures will be modified accordingly. [[ ]] there is no change in the neutronflux experienced by the NMP2 TIPs resulting from the MELLLA+ operating domain expansion. [[ ]] The TIPs are installed at NMP2 inaccordance with the requirements established by the GEH design specifications. No furtherevaluation of these topics is required for MELLLA+.[ 1]]5.2 BOP MONITORING AND CONTROLOperation of the plant in the MELLLA+ domain has no effect on the BOP systeminstrumentation and control devices. The topics addressed in this evaluation are:5-3 NEDO-33576 REVISION 0NON-PROPRIETARY INFORMATION -CLASS I (PUBLIC)Topic M+LTR Disposition NMP2 ResultPressure Control SystemTurbine Steam Bypass System (Nomial Operation) Turbine Steam Bypass System (Safety Analysis) Feedwater Control System (Normal Operation) Feedwater Control System (Safety Analysis) Leak Detection System _]5.2.1 Pressure Control System]] Therefore, no further evaluation of this system isrequired as a result of MELLLA+.[[ ]] for NMP2, there are no increases in reactor operating